Stockfish 10

Official release version of Stockfish 10.

This is also the 10th anniversary version of the Stockfish project, which
started exactly ten years ago! I wish to extend a huge thank you to
all contributors and authors in our amazing community :-)

Bench: 3939338

.travis.yml

@@ -9,20 +9,21 @@ matrix:
       addons:
         apt:
           sources: ['ubuntu-toolchain-r-test']
-          packages: ['g++-6', 'g++-6-multilib', 'g++-multilib', 'valgrind']
+          packages: ['g++-7', 'g++-7-multilib', 'g++-multilib', 'valgrind', 'expect', 'curl']
       env:
-        - COMPILER=g++-6
+        - COMPILER=g++-7
         - COMP=gcc
 
     - os: linux
       compiler: clang
       addons:
         apt:
-          sources: ['ubuntu-toolchain-r-test']
-          packages: ['clang', 'g++-multilib', 'valgrind']
+          sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-5.0']
+          packages: ['clang-5.0', 'llvm-5.0-dev', 'g++-multilib', 'valgrind', 'expect', 'curl']
       env:
-        - COMPILER=clang++
+        - COMPILER=clang++-5.0
         - COMP=clang
+        - LDFLAGS=-fuse-ld=gold
 
     - os: osx
       compiler: gcc
@@ -44,12 +45,30 @@ before_script:
   - cd src
 
 script:
-  - make clean && make build ARCH=x86-64 && ./stockfish bench 2>&1 >/dev/null | grep 'Nodes searched' | tee bench1
-  - make clean && make build ARCH=x86-32 && ./stockfish bench 2>&1 >/dev/null | grep 'Nodes searched' | tee bench2
-  - echo "Checking for same bench numbers..."
-  - diff bench1 bench2 > result
-  - test ! -s result
-  # if valgrind is available check the build is without error, reduce depth to speedup testing, but not too shallow to catch more cases.
-  - if [ -x "$(command -v valgrind )" ] ; then make clean && make ARCH=x86-64 debug=yes build && valgrind --error-exitcode=42 ./stockfish bench 128 1 10 default depth 1>/dev/null ; fi
-  # use g++-6 as a proxy for having sanitizers ... might need revision as they become available for more recent versions of clang/gcc than trusty provides
-  - if [[ "$COMPILER" == "g++-6" ]]; then make clean && make ARCH=x86-64 sanitize=yes build && ! ./stockfish bench 2>&1 | grep "runtime error:" ; fi
+  # Obtain bench reference from git log
+  - git log HEAD | grep "\b[Bb]ench[ :]\+[0-9]\{7\}" | head -n 1 | sed "s/[^0-9]*\([0-9]*\).*/\1/g" > git_sig
+  - export benchref=$(cat git_sig)
+  - echo "Reference bench:" $benchref
+  #
+  # Verify bench number against various builds
+  - export CXXFLAGS=-Werror
+  - make clean && make -j2 ARCH=x86-64 optimize=no debug=yes build && ../tests/signature.sh $benchref
+  - make clean && make -j2 ARCH=x86-32 optimize=no debug=yes build && ../tests/signature.sh $benchref
+  - make clean && make -j2 ARCH=x86-32 build && ../tests/signature.sh $benchref
+  - make clean && make -j2 ARCH=x86-64 build && ../tests/signature.sh $benchref
+  #
+  # Check perft and reproducible search
+  - ../tests/perft.sh
+  - ../tests/reprosearch.sh
+  #
+  # Valgrind
+  #
+  - export CXXFLAGS=-O1
+  - if [ -x "$(command -v valgrind )" ]; then make clean && make -j2 ARCH=x86-64 debug=yes optimize=no build > /dev/null && ../tests/instrumented.sh --valgrind; fi
+  - if [ -x "$(command -v valgrind )" ]; then ../tests/instrumented.sh --valgrind-thread; fi
+  #
+  # Sanitizer
+  #
+  # Use g++-7 as a proxy for having sanitizers, might need revision as they become available for more recent versions of clang/gcc
+  - if [[ "$COMPILER" == "g++-7" ]]; then make clean && make -j2 ARCH=x86-64 sanitize=undefined optimize=no debug=yes build > /dev/null && ../tests/instrumented.sh --sanitizer-undefined; fi
+  - if [[ "$COMPILER" == "g++-7" ]]; then make clean && make -j2 ARCH=x86-64 sanitize=thread    optimize=no debug=yes build > /dev/null && ../tests/instrumented.sh --sanitizer-thread; fi

AUTHORS

@@ -1,98 +1,129 @@
-# Generated with git shortlog -sn | cut -c8-', which sorts by commits (manually ordered the first four authors)
+# List of authors for Stockfish, updated for version 10
 
-Tord Romstad
-Marco Costalba
-Joona Kiiski
-Gary Linscott
-lucasart
-mstembera
-Lucas Braesch
-Stefan Geschwentner
-Reuven Peleg
-Chris Caino
-joergoster
-VoyagerOne
-Jean-Francois Romang
-homoSapiensSapiens
-Alain SAVARD
-Arjun Temurnikar
-Stéphane Nicolet
-Uri Blass
-jundery
-Ralph Stößer
-Ajith
-Leonid Pechenik
-Stefano80
-Tom Vijlbrief
-hxim
-snicolet
-Daylen Yang
-Henri Wiechers
-Jonathan Calovski
-mbootsector
-David Zar
-Eelco de Groot
-Jerry Donald
-Joerg Oster
-Jörg Oster
-Ryan Schmitt
-mcostalba
+Tord Romstad (romstad)
+Marco Costalba (mcostalba)
+Joona Kiiski (zamar)
+Gary Linscott (glinscott)
+
+Aditya (absimaldata)
+Ajith Chandy Jose (ajithcj)
+Alain Savard (Rocky640)
 Alexander Kure
-Dan Schmidt
-H. Felix Wittmann
-Joseph R. Prostko
-Justin Blanchard
-Linus Arver
-NicklasPersson
-Rodrigo Exterckötter Tjäder
-Ron Britvich
-Ronald de Man
-RyanTaker
-Vince Negri
-ceebo
-jhellis3
-ppigazzini
-shane31
+Ali AlZhrani (Cooffe)
+Andrew Grant (AndyGrant)
+Andrey Neporada (nepal)
 Andy Duplain
+Aram Tumanian (atumanian)
+Arjun Temurnikar
 Auguste Pop
 Balint Pfliegel
-Chris Cain
-DU-jdto
+Ben Koshy (BKSpurgeon)
+Bill Henry (VoyagerOne)
+braich
+Brian Sheppard (SapphireBrand)
+Bryan Cross (crossbr)
+Bujun Guo (noobpwnftw)
+Chris Cain (ceebo)
+Dan Schmidt
+Daniel Dugovic (ddugovic)
 Dariusz Orzechowski
+David Zar
+Daylen Yang (daylen)
 DiscanX
+Eelco de Groot
+ElbertoOne
+erbsenzaehler
 Ernesto Gatti
+Fabian Beuke (madnight)
+Fabian Fichter (ianfab)
+fanon
+Fauzi Akram Dabat (FauziAkram)
+Felix Wittmann
+gamander
+gguliash
+Gian-Carlo Pascutto (gcp)
+Gontran Lemaire (gonlem)
+Goodkov Vasiliy Aleksandrovich (goodkov)
 Gregor Cramer
-Guenther Demetz
-Hiraoka Takuya
+GuardianRM
+Günther Demetz (pb00067, pb00068)
+Guy Vreuls (gvreuls)
+Henri Wiechers
+Hiraoka Takuya (HiraokaTakuya)
+homoSapiensSapiens
 Hongzhi Cheng
-Joseph Hellis
+Ivan Ivec (IIvec)
+Jacques B. (Timshel)
+Jan Ondruš (hxim)
+Jared Kish (Kurtbusch)
+Jarrod Torriero (DU-jdto)
+Jean-Francois Romang (jromang)
+Jerry Donald Watson (jerrydonaldwatson)
+Jonathan Calovski (Mysseno)
+Jonathan D. (SFisGOD)
+Joost VandeVondele (vondele)
+Jörg Oster (joergoster)
+Joseph Ellis (jhellis3)
+Joseph R. Prostko
+jundery
+Justin Blanchard
 Kelly Wilson
-Ken T Takusagawa
+Ken Takusagawa
+kinderchocolate
+Kiran Panditrao (Krgp)
 Kojirion
-Luca Brivio
-Matt Sullivan
-Matthew Lai
+Leonardo Ljubičić (ICCF World Champion)
+Leonid Pechenik (lp--)
+Linus Arver
+loco-loco
+Luca Brivio (lucabrivio)
+Lucas Braesch (lucasart)
+Lyudmil Antonov (lantonov)
+Matthew Lai (matthewlai)
 Matthew Sullivan
-Michel Van den Bergh
-Mysseno
+Mark Tenzer (31m059)
+Michael Byrne (MichaelB7)
+Michael Stembera (mstembera)
+Michael Chaly (Vizvezdenec)
+Michel Van den Bergh (vdbergh)
+Miguel Lahoz (miguel-l)
+Mikael Bäckman (mbootsector)
+Mike Whiteley (protonspring)
+Miroslav Fontán (Hexik)
+Moez Jellouli (MJZ1977)
+Mohammed Li (tthsqe12)
+Nathan Rugg (nmrugg)
+Nicklas Persson (NicklasPersson)
+Niklas Fiekas (niklasf)
+Ondrej Mosnáček (WOnder93)
 Oskar Werkelin Ahlin
 Pablo Vazquez
 Pascal Romaret
-Ralph Stoesser
-Ralph Stößer
-Raminder Singh
-Richard Lloyd
-Ryan Takker
-Stephane Nicolet
-Thanar2
-absimaldata
-braich
-gguliash
-kinderchocolate
-loco-loco
+Pasquale Pigazzini (ppigazzini)
+Patrick Jansen (mibere)
 pellanda
+Peter Zsifkovits (CoffeeOne)
+Ralph Stößer (Ralph Stoesser)
+Raminder Singh
 renouve
+Reuven Peleg
+Richard Lloyd
+Rodrigo Exterckötter Tjäder
+Ron Britvich (Britvich)
+Ronald de Man (syzygy1)
+Ryan Schmitt
+Ryan Takker
+Sebastian Buchwald (UniQP)
+Sergei Antonov (saproj)
 sf-x
+shane31
+Steinar Gunderson (sesse)
+Stefan Geschwentner (locutus2)
+Stefano Cardanobile (Stefano80)
+Stéphane Nicolet (snicolet)
+Thanar2
 thaspel
-unknown
-uriblass
+Tom Vijlbrief (tomtor)
+Torsten Franz (torfranz)
+Uri Blass (uriblass)
+Vince Negri

Readme.md

@@ -10,7 +10,7 @@ Partner or Fritz) in order to be used comfortably. Read the
 documentation for your GUI of choice for information about how to use
 Stockfish with it.
 
-This version of Stockfish supports up to 128 cores. The engine defaults
+This version of Stockfish supports up to 512 cores. The engine defaults
 to one search thread, so it is therefore recommended to inspect the value of
 the *Threads* UCI parameter, and to make sure it equals the number of CPU
 cores on your computer.
@@ -59,7 +59,7 @@ The "SyzygyProbeLimit" option should normally be left at its default value.
 
 **What to expect**
 If the engine is searching a position that is not in the tablebases (e.g.
-a position with 7 pieces), it will access the tablebases during the search.
+a position with 8 pieces), it will access the tablebases during the search.
 If the engine reports a very large score (typically 123.xx), this means
 that it has found a winning line into a tablebase position.
 
@@ -96,6 +96,18 @@ compile (for instance with Microsoft MSVC) you need to manually
 set/unset some switches in the compiler command line; see file *types.h*
 for a quick reference.
 
+### Resource For Understanding the Code Base
+
+* [Chess Programming Wiki](https://www.chessprogramming.org/Main_Page) 
+has good overall chess engines explanations 
+(techniques used here are well explained like hash maps etc), it was 
+also recommended by the [support team at stockfish.](http://support.stockfishchess.org/discussions/questions/1132-how-to-understand-stockfish-sources)
+
+* [Here](https://www.chessprogramming.org/Stockfish) you can find a set 
+of features and techniques used by Stockfish and each of them is explained 
+at the wiki, however, it's a generic way rather than focusing on Stockfish's 
+own implementation, but it will still help you.
+
 
 ### Terms of use
 

Top CPU Contributors.txt

@@ -0,0 +1,146 @@
+Contributors with >10,000 CPU hours as of November 4, 2018
+Thank you!
+
+Username               CPU Hours   Games played
+noobpwnftw             3730975     292309380   
+mibere                 535242      43333774    
+crunchy                375564      29121434    
+cw                     371664      28748719    
+fastgm                 318178      22283584    
+JojoM                  295354      20958931    
+dew                    215476      17079219    
+ctoks                  214031      17312035    
+glinscott              204517      13932027    
+bking_US               187568      12233168    
+velislav               168404      13336219    
+CSU_Dynasty            168069      14417712    
+Thanar                 162373      13842179    
+spams                  149531      10940322    
+Fisherman              141137      12099359    
+drabel                 134441      11180178    
+leszek                 133658      9812120     
+marrco                 133566      10115202    
+sqrt2                  128420      10022279    
+vdbergh                123230      9200516     
+tvijlbrief             123007      9498831     
+vdv                    120381      8555423     
+malala                 117291      8126488     
+dsmith                 114010      7622414     
+BrunoBanani            104938      7448565     
+CoffeeOne              100042      4593596     
+Data                   94621       8433010     
+mgrabiak               92248       7787406     
+bcross                 89440       8506568     
+brabos                 81868       6647613     
+BRAVONE                80811       5341681     
+psk                    77195       6156031     
+nordlandia             74833       6231930     
+robal                  72818       5969856     
+TueRens                72523       6383294     
+sterni1971             71049       5647590     
+sunu                   65855       5360884     
+mhoram                 65034       5192880     
+davar                  64794       5457564     
+nssy                   64607       5371952     
+Pking_cda              64499       5704075     
+biffhero               63557       5480444     
+teddybaer              62147       5585620     
+solarlight             61278       5402642     
+ElbertoOne             60156       5504304     
+jromang                58854       4704502     
+dv8silencer            57421       3961325     
+tinker                 56039       4204914     
+Freja                  50331       3808121     
+renouve                50318       3544864     
+robnjr                 47504       4131742     
+grandphish2            47377       4110003     
+eva42                  46857       4075716     
+ttruscott              46802       3811534     
+finfish                46244       3481661     
+rap                    46201       3219490     
+ronaldjerum            45641       3964331     
+xoto                   44998       4170431     
+gvreuls                44359       3902234     
+bigpen0r               41780       3448224     
+Bobo1239               40767       3657490     
+Antihistamine          39218       2792761     
+mhunt                  38991       2697512     
+racerschmacer          38929       3756111     
+VoyagerOne             35896       3378887     
+homyur                 35561       3012398     
+rkl                    33217       2978536     
+pb00067                33034       2803485     
+speedycpu              32043       2531964     
+SC                     31954       2848432     
+EthanOConnor           31638       2143255     
+oryx                   30962       2899534     
+gri                    30108       2429137     
+csnodgrass             29396       2808611     
+Garf                   28887       2873564     
+Pyafue                 28885       1986098     
+jkiiski                28014       1923255     
+slakovv                27017       2031279     
+Prcuvu                 26300       2307154     
+hyperbolic.tom         26248       2200777     
+jbwiebe                25663       2129063     
+anst                   25525       2279159     
+Patrick_G              24222       1835674     
+nabildanial            23524       1586321     
+achambord              23495       1942546     
+Sharaf_DG              22975       1790697     
+chriswk                22876       1947731     
+ncfish1                22689       1830009     
+cuistot                22201       1383031     
+Zirie                  21171       1493227     
+Isidor                 20634       1736219     
+JanErik                20596       1791991     
+xor12                  20535       1819280     
+team-oh                20364       1653708     
+nesoneg                20264       1493435     
+dex                    20110       1682756     
+rstoesser              19802       1335177     
+Vizvezdenec            19750       1695579     
+eastorwest             19531       1841839     
+sg4032                 18913       1720157     
+horst.prack            18425       1708197     
+cisco2015              18408       1793774     
+ianh2105               18133       1668562     
+MazeOfGalious          18022       1644593     
+ville                  17900       1539130     
+j3corre                17607       975954      
+eudhan                 17502       1424648     
+jmdana                 17351       1287546     
+iisiraider             17175       1118788     
+jundery                17172       1115855     
+wei                    16852       1822582     
+SFTUser                16635       1363975     
+purplefishies          16621       1106850     
+DragonLord             16599       1252348     
+chris                  15274       1575333     
+IgorLeMasson           15201       1364148     
+dju                    15074       914278      
+Flopzee                14700       1331632     
+OssumOpossum           14149       1029265     
+enedene                13762       935618      
+ako027ako              13442       1250249     
+AdrianSA               13324       924980      
+bpfliegel              13318       886523      
+Nikolay.IT             13260       1155612     
+jpulman                12776       854815      
+joster                 12438       988413      
+fatmurphy              12015       901134      
+Nesa92                 11711       1132245     
+Adrian.Schmidt123      11542       898699      
+modolief               11228       926456      
+Dark_wizzie            11214       1017910     
+mschmidt               10973       818594      
+Andrew Grant           10780       947859      
+infinity               10762       746397      
+SapphireBrand          10692       1024604     
+Thomas A. Anderson     10553       736094      
+basepi                 10434       935168      
+lantonov               10325       972610      
+pgontarz               10294       878746      
+Spprtr                 10189       823246      
+crocogoat              10115       1017325     
+stocky                 10083       718114      

appveyor.yml

@@ -1,5 +1,5 @@
 version: 1.0.{build}
-clone_depth: 5
+clone_depth: 50
 
 branches:
   only:
@@ -13,10 +13,11 @@ os: Visual Studio 2015
 platform:
   - x86
   - x64
-  - Any CPU
 
 # build Configuration, i.e. Debug, Release, etc.
-configuration: Debug
+configuration:
+  - Debug
+  - Release
 
 matrix:
   # The build fail immediately once one of the job fails
@@ -28,18 +29,43 @@ init:
   - msbuild /version
 
 before_build:
-  - cd src
-  - echo project (Stockfish) >> CMakeLists.txt
-  - echo add_executable(stockfish benchmark.cpp bitbase.cpp bitboard.cpp endgame.cpp evaluate.cpp >> CMakeLists.txt
-  - echo main.cpp material.cpp misc.cpp movegen.cpp movepick.cpp pawns.cpp position.cpp psqt.cpp >> CMakeLists.txt
-  - echo search.cpp thread.cpp timeman.cpp tt.cpp uci.cpp ucioption.cpp syzygy/tbprobe.cpp) >> CMakeLists.txt
-  - echo set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/src) >> CMakeLists.txt
-#   - echo target_compile_options(stockfish PUBLIC "/Ox") >> CMakeLists.txt
+  - ps: |
+      # Get sources
+      $src = get-childitem -Path *.cpp -Recurse | select -ExpandProperty FullName
+      $src = $src -join ' '
+      $src = $src.Replace("\", "/")
+
+      # Build CMakeLists.txt
+      $t = 'cmake_minimum_required(VERSION 3.8)',
+           'project(Stockfish)',
+           'set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/src)',
+           'set(source_files', $src, ')',
+           'add_executable(stockfish ${source_files})'
+
+      # Write CMakeLists.txt withouth BOM
+      $MyPath = (Get-Item -Path "." -Verbose).FullName + '\CMakeLists.txt'
+      $Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding $False
+      [System.IO.File]::WriteAllLines($MyPath, $t, $Utf8NoBomEncoding)
+
+      # Obtain bench reference from git log
+      $b = git log HEAD | sls "\b[Bb]ench[ :]+[0-9]{7}" | select -first 1
+      $bench = $b -match '\D+(\d+)' | % { $matches[1] }
+      Write-Host "Reference bench:" $bench
+      $g = "Visual Studio 14 2015"
+      If (${env:PLATFORM} -eq 'x64') { $g = $g + ' Win64' }
+      cmake -G "${g}" .
+      Write-Host "Generated files for: " $g
 
 build_script:
-  - cmake -G "Visual Studio 14 2015 Win64" .
-  - cmake --build .
+  - cmake --build . --config %CONFIGURATION% -- /verbosity:minimal
 
 before_test:
-  - cd Debug
-  - stockfish.exe bench > null
+  - cd src/%CONFIGURATION%
+  - stockfish bench 2> out.txt >NUL
+  - ps: |
+      # Verify bench number
+      $s = (gc "./out.txt" | out-string)
+      $r = ($s -match 'Nodes searched \D+(\d+)' | % { $matches[1] })
+      Write-Host "Engine bench:" $r
+      Write-Host "Reference bench:" $bench
+      If ($r -ne $bench) { exit 1 }

src/Makefile

@@ -1,7 +1,7 @@
 # Stockfish, a UCI chess playing engine derived from Glaurung 2.1
 # Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
 # Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-# Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+# Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 #
 # Stockfish is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -21,14 +21,12 @@
 ### Section 1. General Configuration
 ### ==========================================================================
 
-### Establish the operating system name
-KERNEL = $(shell uname -s)
-ifeq ($(KERNEL),Linux)
-	OS = $(shell uname -o)
-endif
-
 ### Executable name
+ifeq ($(COMP),mingw)
+EXE = stockfish.exe
+else
 EXE = stockfish
+endif
 
 ### Installation dir definitions
 PREFIX = /usr/local
@@ -42,6 +40,12 @@ OBJS = benchmark.o bitbase.o bitboard.o endgame.o evaluate.o main.o \
 	material.o misc.o movegen.o movepick.o pawns.o position.o psqt.o \
 	search.o thread.o timeman.o tt.o uci.o ucioption.o syzygy/tbprobe.o
 
+### Establish the operating system name
+KERNEL = $(shell uname -s)
+ifeq ($(KERNEL),Linux)
+	OS = $(shell uname -o)
+endif
+
 ### ==========================================================================
 ### Section 2. High-level Configuration
 ### ==========================================================================
@@ -50,7 +54,9 @@ OBJS = benchmark.o bitbase.o bitboard.o endgame.o evaluate.o main.o \
 # ----------------------------------------------------------------------------
 #
 # debug = yes/no      --- -DNDEBUG         --- Enable/Disable debug mode
-# sanitize = yes/no   --- (-fsanitize )    --- enable undefined behavior checks
+# sanitize = undefined/thread/no (-fsanitize )
+#                     --- ( undefined )    --- enable undefined behavior checks
+#                     --- ( thread    )    --- enable threading error  checks
 # optimize = yes/no   --- (-O3/-fast etc.) --- Enable/Disable optimizations
 # arch = (name)       --- (-arch)          --- Target architecture
 # bits = 64/32        --- -DIS_64BIT       --- 64-/32-bit operating system
@@ -139,7 +145,7 @@ endif
 
 ### 3.1 Selecting compiler (default = gcc)
 
-CXXFLAGS += -Wall -Wcast-qual -fno-exceptions -fno-rtti -std=c++11 $(EXTRACXXFLAGS)
+CXXFLAGS += -Wall -Wcast-qual -fno-exceptions -std=c++11 $(EXTRACXXFLAGS)
 DEPENDFLAGS += -std=c++11
 LDFLAGS += $(EXTRALDFLAGS)
 
@@ -155,9 +161,11 @@ ifeq ($(COMP),gcc)
 	ifeq ($(ARCH),armv7)
 		ifeq ($(OS),Android)
 			CXXFLAGS += -m$(bits)
+			LDFLAGS += -m$(bits)
 		endif
 	else
 		CXXFLAGS += -m$(bits)
+		LDFLAGS += -m$(bits)
 	endif
 
 	ifneq ($(KERNEL),Darwin)
@@ -201,6 +209,12 @@ ifeq ($(COMP),clang)
 	CXX=clang++
 	CXXFLAGS += -pedantic -Wextra -Wshadow
 
+	ifneq ($(KERNEL),Darwin)
+	ifneq ($(KERNEL),OpenBSD)
+		LDFLAGS += -latomic
+	endif
+	endif
+
 	ifeq ($(ARCH),armv7)
 		ifeq ($(OS),Android)
 			CXXFLAGS += -m$(bits)
@@ -210,23 +224,19 @@ ifeq ($(COMP),clang)
 		CXXFLAGS += -m$(bits)
 		LDFLAGS += -m$(bits)
 	endif
-
-	ifeq ($(KERNEL),Darwin)
-		CXXFLAGS += -stdlib=libc++
-		DEPENDFLAGS += -stdlib=libc++
-	endif
 endif
 
 ifeq ($(comp),icc)
-	profile_prepare = icc-profile-prepare
 	profile_make = icc-profile-make
 	profile_use = icc-profile-use
-	profile_clean = icc-profile-clean
 else
-	profile_prepare = gcc-profile-prepare
+ifeq ($(comp),clang)
+	profile_make = clang-profile-make
+	profile_use = clang-profile-use
+else
 	profile_make = gcc-profile-make
 	profile_use = gcc-profile-use
-	profile_clean = gcc-profile-clean
+endif
 endif
 
 ifeq ($(KERNEL),Darwin)
@@ -263,8 +273,9 @@ else
 endif
 
 ### 3.2.2 Debugging with undefined behavior sanitizers
-ifeq ($(sanitize),yes)
-	CXXFLAGS += -g3 -fsanitize=undefined
+ifneq ($(sanitize),no)
+        CXXFLAGS += -g3 -fsanitize=$(sanitize) -fuse-ld=gold
+        LDFLAGS += -fsanitize=$(sanitize) -fuse-ld=gold
 endif
 
 ### 3.3 Optimization
@@ -273,41 +284,16 @@ ifeq ($(optimize),yes)
 	CXXFLAGS += -O3
 
 	ifeq ($(comp),gcc)
-
-		ifeq ($(KERNEL),Darwin)
-			ifeq ($(arch),i386)
-				CXXFLAGS += -mdynamic-no-pic
-			endif
-			ifeq ($(arch),x86_64)
-				CXXFLAGS += -mdynamic-no-pic
-			endif
-		endif
-
 		ifeq ($(OS), Android)
 			CXXFLAGS += -fno-gcse -mthumb -march=armv7-a -mfloat-abi=softfp
 		endif
 	endif
-
-	ifeq ($(comp),icc)
+	
+	ifeq ($(comp),$(filter $(comp),gcc clang icc))
 		ifeq ($(KERNEL),Darwin)
 			CXXFLAGS += -mdynamic-no-pic
 		endif
 	endif
-
-	ifeq ($(comp),clang)
-		ifeq ($(KERNEL),Darwin)
-			ifeq ($(pext),no)
-				CXXFLAGS += -flto
-				LDFLAGS += $(CXXFLAGS)
-			endif
-			ifeq ($(arch),i386)
-				CXXFLAGS += -mdynamic-no-pic
-			endif
-			ifeq ($(arch),x86_64)
-				CXXFLAGS += -mdynamic-no-pic
-			endif
-		endif
-	endif
 endif
 
 ### 3.4 Bits
@@ -345,24 +331,20 @@ endif
 ### 3.8 Link Time Optimization, it works since gcc 4.5 but not on mingw under Windows.
 ### This is a mix of compile and link time options because the lto link phase
 ### needs access to the optimization flags.
-ifeq ($(comp),gcc)
-	ifeq ($(optimize),yes)
-	ifeq ($(debug),no)
+ifeq ($(optimize),yes)
+ifeq ($(debug), no)
+	ifeq ($(comp),$(filter $(comp),gcc clang))
+		CXXFLAGS += -flto
+		LDFLAGS += $(CXXFLAGS)
+	endif
+
+	ifeq ($(comp),mingw)
+	ifeq ($(KERNEL),Linux)
 		CXXFLAGS += -flto
 		LDFLAGS += $(CXXFLAGS)
 	endif
 	endif
 endif
-
-ifeq ($(comp),mingw)
-	ifeq ($(KERNEL),Linux)
-	ifeq ($(optimize),yes)
-	ifeq ($(debug),no)
-		CXXFLAGS += -flto
-		LDFLAGS += $(CXXFLAGS)
-	endif
-	endif
-	endif
 endif
 
 ### 3.9 Android 5 can only run position independent executables. Note that this
@@ -423,30 +405,27 @@ help:
 	@echo ""
 
 
-.PHONY: build profile-build
-build:
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) config-sanity
+.PHONY: help build profile-build strip install clean objclean profileclean help \
+        config-sanity icc-profile-use icc-profile-make gcc-profile-use gcc-profile-make \
+        clang-profile-use clang-profile-make
+
+build: config-sanity
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) all
 
-profile-build:
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) config-sanity
+profile-build: config-sanity objclean profileclean
 	@echo ""
-	@echo "Step 0/4. Preparing for profile build."
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_prepare)
-	@echo ""
-	@echo "Step 1/4. Building executable for benchmark ..."
-	@touch *.cpp *.h syzygy/*.cpp syzygy/*.h
+	@echo "Step 1/4. Building instrumented executable ..."
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_make)
 	@echo ""
 	@echo "Step 2/4. Running benchmark for pgo-build ..."
 	$(PGOBENCH) > /dev/null
 	@echo ""
-	@echo "Step 3/4. Building final executable ..."
-	@touch *.cpp *.h syzygy/*.cpp syzygy/*.h
+	@echo "Step 3/4. Building optimized executable ..."
+	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) objclean
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_use)
 	@echo ""
 	@echo "Step 4/4. Deleting profile data ..."
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_clean)
+	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) profileclean
 
 strip:
 	strip $(EXE)
@@ -456,8 +435,19 @@ install:
 	-cp $(EXE) $(BINDIR)
 	-strip $(BINDIR)/$(EXE)
 
-clean:
-	$(RM) $(EXE) $(EXE).exe *.o .depend *~ core bench.txt *.gcda ./syzygy/*.o ./syzygy/*.gcda
+#clean all
+clean: objclean profileclean
+	@rm -f .depend *~ core
+
+# clean binaries and objects
+objclean:
+	@rm -f $(EXE) *.o ./syzygy/*.o
+
+# clean auxiliary profiling files
+profileclean:
+	@rm -rf profdir
+	@rm -f bench.txt *.gcda ./syzygy/*.gcda *.gcno ./syzygy/*.gcno
+	@rm -f stockfish.profdata *.profraw
 
 default:
 	help
@@ -472,6 +462,7 @@ config-sanity:
 	@echo ""
 	@echo "Config:"
 	@echo "debug: '$(debug)'"
+	@echo "sanitize: '$(sanitize)'"
 	@echo "optimize: '$(optimize)'"
 	@echo "arch: '$(arch)'"
 	@echo "bits: '$(bits)'"
@@ -490,6 +481,7 @@ config-sanity:
 	@echo "Testing config sanity. If this fails, try 'make help' ..."
 	@echo ""
 	@test "$(debug)" = "yes" || test "$(debug)" = "no"
+	@test "$(sanitize)" = "undefined" || test "$(sanitize)" = "thread" || test "$(sanitize)" = "no"
 	@test "$(optimize)" = "yes" || test "$(optimize)" = "no"
 	@test "$(arch)" = "any" || test "$(arch)" = "x86_64" || test "$(arch)" = "i386" || \
 	 test "$(arch)" = "ppc64" || test "$(arch)" = "ppc" || test "$(arch)" = "armv7"
@@ -503,8 +495,18 @@ config-sanity:
 $(EXE): $(OBJS)
 	$(CXX) -o $@ $(OBJS) $(LDFLAGS)
 
-gcc-profile-prepare:
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) gcc-profile-clean
+clang-profile-make:
+	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) \
+	EXTRACXXFLAGS='-fprofile-instr-generate ' \
+	EXTRALDFLAGS=' -fprofile-instr-generate' \
+	all
+
+clang-profile-use:
+	llvm-profdata merge -output=stockfish.profdata *.profraw
+	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) \
+	EXTRACXXFLAGS='-fprofile-instr-use=stockfish.profdata' \
+	EXTRALDFLAGS='-fprofile-use ' \
+	all
 
 gcc-profile-make:
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) \
@@ -518,14 +520,8 @@ gcc-profile-use:
 	EXTRALDFLAGS='-lgcov' \
 	all
 
-gcc-profile-clean:
-	@rm -rf *.gcda *.gcno syzygy/*.gcda syzygy/*.gcno bench.txt
-
-icc-profile-prepare:
-	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) icc-profile-clean
-	@mkdir profdir
-
 icc-profile-make:
+	@mkdir -p profdir
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) \
 	EXTRACXXFLAGS='-prof-gen=srcpos -prof_dir ./profdir' \
 	all
@@ -535,9 +531,6 @@ icc-profile-use:
 	EXTRACXXFLAGS='-prof_use -prof_dir ./profdir' \
 	all
 
-icc-profile-clean:
-	@rm -rf profdir bench.txt
-
 .depend:
 	-@$(CXX) $(DEPENDFLAGS) -MM $(OBJS:.o=.cpp) > $@ 2> /dev/null
 

src/benchmark.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -23,23 +23,20 @@
 #include <istream>
 #include <vector>
 
-#include "misc.h"
 #include "position.h"
-#include "search.h"
-#include "thread.h"
-#include "uci.h"
 
 using namespace std;
 
 namespace {
 
 const vector<string> Defaults = {
+  "setoption name UCI_Chess960 value false",
   "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
   "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 10",
   "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 11",
   "4rrk1/pp1n3p/3q2pQ/2p1pb2/2PP4/2P3N1/P2B2PP/4RRK1 b - - 7 19",
-  "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14",
-  "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14",
+  "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14 moves d4e6",
+  "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14 moves g2g4",
   "r3r1k1/2p2ppp/p1p1bn2/8/1q2P3/2NPQN2/PPP3PP/R4RK1 b - - 2 15",
   "r1bbk1nr/pp3p1p/2n5/1N4p1/2Np1B2/8/PPP2PPP/2KR1B1R w kq - 0 13",
   "r1bq1rk1/ppp1nppp/4n3/3p3Q/3P4/1BP1B3/PP1N2PP/R4RK1 w - - 1 16",
@@ -52,7 +49,7 @@ const vector<string> Defaults = {
   "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26",
   "6k1/6p1/6Pp/ppp5/3pn2P/1P3K2/1PP2P2/3N4 b - - 0 1",
   "3b4/5kp1/1p1p1p1p/pP1PpP1P/P1P1P3/3KN3/8/8 w - - 0 1",
-  "2K5/p7/7P/5pR1/8/5k2/r7/8 w - - 0 1",
+  "2K5/p7/7P/5pR1/8/5k2/r7/8 w - - 0 1 moves g5g6 f3e3 g6g5 e3f3",
   "8/6pk/1p6/8/PP3p1p/5P2/4KP1q/3Q4 w - - 0 1",
   "7k/3p2pp/4q3/8/4Q3/5Kp1/P6b/8 w - - 0 1",
   "8/2p5/8/2kPKp1p/2p4P/2P5/3P4/8 w - - 0 1",
@@ -79,28 +76,35 @@ const vector<string> Defaults = {
   "8/R7/2q5/8/6k1/8/1P5p/K6R w - - 0 124", // Draw
 
   // Mate and stalemate positions
+  "6k1/3b3r/1p1p4/p1n2p2/1PPNpP1q/P3Q1p1/1R1RB1P1/5K2 b - - 0 1",
+  "r2r1n2/pp2bk2/2p1p2p/3q4/3PN1QP/2P3R1/P4PP1/5RK1 w - - 0 1",
   "8/8/8/8/8/6k1/6p1/6K1 w - -",
-  "5k2/5P2/5K2/8/8/8/8/8 b - -",
-  "8/8/8/8/8/4k3/4p3/4K3 w - -",
-  "8/8/8/8/8/5K2/8/3Q1k2 b - -",
-  "7k/7P/6K1/8/3B4/8/8/8 b - -"
+  "7k/7P/6K1/8/3B4/8/8/8 b - -",
+
+  // Chess 960
+  "setoption name UCI_Chess960 value true",
+  "bbqnnrkr/pppppppp/8/8/8/8/PPPPPPPP/BBQNNRKR w KQkq - 0 1 moves g2g3 d7d5 d2d4 c8h3 c1g5 e8d6 g5e7 f7f6",
+  "setoption name UCI_Chess960 value false"
 };
 
 } // namespace
 
-/// benchmark() runs a simple benchmark by letting Stockfish analyze a set
-/// of positions for a given limit each. There are five parameters: the
-/// transposition table size, the number of search threads that should
-/// be used, the limit value spent for each position (optional, default is
-/// depth 13), an optional file name where to look for positions in FEN
-/// format (defaults are the positions defined above) and the type of the
-/// limit value: depth (default), time in millisecs or number of nodes.
+/// setup_bench() builds a list of UCI commands to be run by bench. There
+/// are five parameters: TT size in MB, number of search threads that
+/// should be used, the limit value spent for each position, a file name
+/// where to look for positions in FEN format and the type of the limit:
+/// depth, perft, nodes and movetime (in millisecs).
+///
+/// bench -> search default positions up to depth 13
+/// bench 64 1 15 -> search default positions up to depth 15 (TT = 64MB)
+/// bench 64 4 5000 current movetime -> search current position with 4 threads for 5 sec
+/// bench 64 1 100000 default nodes -> search default positions for 100K nodes each
+/// bench 16 1 5 default perft -> run a perft 5 on default positions
 
-void benchmark(const Position& current, istream& is) {
+vector<string> setup_bench(const Position& current, istream& is) {
 
-  string token;
-  vector<string> fens;
-  Search::LimitsType limits;
+  vector<string> fens, list;
+  string go, token;
 
   // Assign default values to missing arguments
   string ttSize    = (is >> token) ? token : "16";
@@ -109,21 +113,7 @@ void benchmark(const Position& current, istream& is) {
   string fenFile   = (is >> token) ? token : "default";
   string limitType = (is >> token) ? token : "depth";
 
-  Options["Hash"]    = ttSize;
-  Options["Threads"] = threads;
-  Search::clear();
-
-  if (limitType == "time")
-      limits.movetime = stoi(limit); // movetime is in millisecs
-
-  else if (limitType == "nodes")
-      limits.nodes = stoi(limit);
-
-  else if (limitType == "mate")
-      limits.mate = stoi(limit);
-
-  else
-      limits.depth = stoi(limit);
+  go = "go " + limitType + " " + limit;
 
   if (fenFile == "default")
       fens = Defaults;
@@ -139,7 +129,7 @@ void benchmark(const Position& current, istream& is) {
       if (!file.is_open())
       {
           cerr << "Unable to open file " << fenFile << endl;
-          return;
+          exit(EXIT_FAILURE);
       }
 
       while (getline(file, fen))
@@ -149,35 +139,18 @@ void benchmark(const Position& current, istream& is) {
       file.close();
   }
 
-  uint64_t nodes = 0;
-  TimePoint elapsed = now();
-  Position pos;
-
-  for (size_t i = 0; i < fens.size(); ++i)
-  {
-      StateListPtr states(new std::deque<StateInfo>(1));
-      pos.set(fens[i], Options["UCI_Chess960"], &states->back(), Threads.main());
-
-      cerr << "\nPosition: " << i + 1 << '/' << fens.size() << endl;
-
-      if (limitType == "perft")
-          nodes += Search::perft(pos, limits.depth * ONE_PLY);
+  list.emplace_back("ucinewgame");
+  list.emplace_back("setoption name Threads value " + threads);
+  list.emplace_back("setoption name Hash value " + ttSize);
 
+  for (const string& fen : fens)
+      if (fen.find("setoption") != string::npos)
+          list.emplace_back(fen);
       else
       {
-          limits.startTime = now();
-          Threads.start_thinking(pos, states, limits);
-          Threads.main()->wait_for_search_finished();
-          nodes += Threads.nodes_searched();
+          list.emplace_back("position fen " + fen);
+          list.emplace_back(go);
       }
-  }
 
-  elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
-
-  dbg_print(); // Just before exiting
-
-  cerr << "\n==========================="
-       << "\nTotal time (ms) : " << elapsed
-       << "\nNodes searched  : " << nodes
-       << "\nNodes/second    : " << 1000 * nodes / elapsed << endl;
+  return list;
 }

src/bitbase.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -29,7 +29,7 @@
 namespace {
 
   // There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
-  const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+  constexpr unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
 
   // Each uint32_t stores results of 32 positions, one per bit
   uint32_t KPKBitbase[MAX_INDEX / 32];
@@ -111,13 +111,13 @@ namespace {
     ksq[WHITE] = Square((idx >>  0) & 0x3F);
     ksq[BLACK] = Square((idx >>  6) & 0x3F);
     us         = Color ((idx >> 12) & 0x01);
-    psq        = make_square(File((idx >> 13) & 0x3), RANK_7 - Rank((idx >> 15) & 0x7));
+    psq        = make_square(File((idx >> 13) & 0x3), Rank(RANK_7 - ((idx >> 15) & 0x7)));
 
     // Check if two pieces are on the same square or if a king can be captured
     if (   distance(ksq[WHITE], ksq[BLACK]) <= 1
         || ksq[WHITE] == psq
         || ksq[BLACK] == psq
-        || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+        || (us == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK])))
         result = INVALID;
 
     // Immediate win if a pawn can be promoted without getting captured
@@ -125,13 +125,13 @@ namespace {
              && rank_of(psq) == RANK_7
              && ksq[us] != psq + NORTH
              && (    distance(ksq[~us], psq + NORTH) > 1
-                 || (StepAttacksBB[KING][ksq[us]] & (psq + NORTH))))
+                 || (PseudoAttacks[KING][ksq[us]] & (psq + NORTH))))
         result = WIN;
 
     // Immediate draw if it is a stalemate or a king captures undefended pawn
     else if (   us == BLACK
-             && (  !(StepAttacksBB[KING][ksq[us]] & ~(StepAttacksBB[KING][ksq[~us]] | StepAttacksBB[PAWN][psq]))
-                 || (StepAttacksBB[KING][ksq[us]] & psq & ~StepAttacksBB[KING][ksq[~us]])))
+             && (  !(PseudoAttacks[KING][ksq[us]] & ~(PseudoAttacks[KING][ksq[~us]] | PawnAttacks[~us][psq]))
+                 || (PseudoAttacks[KING][ksq[us]] & psq & ~PseudoAttacks[KING][ksq[~us]])))
         result = DRAW;
 
     // Position will be classified later
@@ -152,12 +152,12 @@ namespace {
     // as WIN, the position is classified as WIN, otherwise the current position is
     // classified as UNKNOWN.
 
-    const Color  Them = (Us == WHITE ? BLACK : WHITE);
-    const Result Good = (Us == WHITE ? WIN   : DRAW);
-    const Result Bad  = (Us == WHITE ? DRAW  : WIN);
+    constexpr Color  Them = (Us == WHITE ? BLACK : WHITE);
+    constexpr Result Good = (Us == WHITE ? WIN   : DRAW);
+    constexpr Result Bad  = (Us == WHITE ? DRAW  : WIN);
 
     Result r = INVALID;
-    Bitboard b = StepAttacksBB[KING][ksq[Us]];
+    Bitboard b = PseudoAttacks[KING][ksq[Us]];
 
     while (b)
         r |= Us == WHITE ? db[index(Them, ksq[Them]  , pop_lsb(&b), psq)]

src/bitboard.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,55 +26,29 @@
 uint8_t PopCnt16[1 << 16];
 int SquareDistance[SQUARE_NB][SQUARE_NB];
 
-Bitboard  RookMasks  [SQUARE_NB];
-Bitboard  RookMagics [SQUARE_NB];
-Bitboard* RookAttacks[SQUARE_NB];
-unsigned  RookShifts [SQUARE_NB];
-
-Bitboard  BishopMasks  [SQUARE_NB];
-Bitboard  BishopMagics [SQUARE_NB];
-Bitboard* BishopAttacks[SQUARE_NB];
-unsigned  BishopShifts [SQUARE_NB];
-
 Bitboard SquareBB[SQUARE_NB];
 Bitboard FileBB[FILE_NB];
 Bitboard RankBB[RANK_NB];
 Bitboard AdjacentFilesBB[FILE_NB];
-Bitboard InFrontBB[COLOR_NB][RANK_NB];
-Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
+Bitboard ForwardRanksBB[COLOR_NB][RANK_NB];
 Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
 Bitboard LineBB[SQUARE_NB][SQUARE_NB];
 Bitboard DistanceRingBB[SQUARE_NB][8];
-Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
+Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB];
 Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
 Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
 Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+Bitboard PawnAttacks[COLOR_NB][SQUARE_NB];
+
+Magic RookMagics[SQUARE_NB];
+Magic BishopMagics[SQUARE_NB];
 
 namespace {
 
-  // De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan
-  const uint64_t DeBruijn64 = 0x3F79D71B4CB0A89ULL;
-  const uint32_t DeBruijn32 = 0x783A9B23;
-
-  int MSBTable[256];            // To implement software msb()
-  Square BSFTable[SQUARE_NB];   // To implement software bitscan
   Bitboard RookTable[0x19000];  // To store rook attacks
   Bitboard BishopTable[0x1480]; // To store bishop attacks
 
-  typedef unsigned (Fn)(Square, Bitboard);
-
-  void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
-                   Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
-
-  // bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses
-  // Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch.
-
-  unsigned bsf_index(Bitboard b) {
-    b ^= b - 1;
-    return Is64Bit ? (b * DeBruijn64) >> 58
-                   : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26;
-  }
-
+  void init_magics(Bitboard table[], Magic magics[], Direction directions[]);
 
   // popcount16() counts the non-zero bits using SWAR-Popcount algorithm
 
@@ -86,46 +60,6 @@ namespace {
   }
 }
 
-#ifdef NO_BSF
-
-/// Software fall-back of lsb() and msb() for CPU lacking hardware support
-
-Square lsb(Bitboard b) {
-  assert(b);
-  return BSFTable[bsf_index(b)];
-}
-
-Square msb(Bitboard b) {
-
-  assert(b);
-  unsigned b32;
-  int result = 0;
-
-  if (b > 0xFFFFFFFF)
-  {
-      b >>= 32;
-      result = 32;
-  }
-
-  b32 = unsigned(b);
-
-  if (b32 > 0xFFFF)
-  {
-      b32 >>= 16;
-      result += 16;
-  }
-
-  if (b32 > 0xFF)
-  {
-      b32 >>= 8;
-      result += 8;
-  }
-
-  return Square(result + MSBTable[b32]);
-}
-
-#endif // ifdef NO_BSF
-
 
 /// Bitboards::pretty() returns an ASCII representation of a bitboard suitable
 /// to be printed to standard output. Useful for debugging.
@@ -155,13 +89,7 @@ void Bitboards::init() {
       PopCnt16[i] = (uint8_t) popcount16(i);
 
   for (Square s = SQ_A1; s <= SQ_H8; ++s)
-  {
-      SquareBB[s] = 1ULL << s;
-      BSFTable[bsf_index(SquareBB[s])] = s;
-  }
-
-  for (Bitboard b = 2; b < 256; ++b)
-      MSBTable[b] = MSBTable[b - 1] + !more_than_one(b);
+      SquareBB[s] = (1ULL << s);
 
   for (File f = FILE_A; f <= FILE_H; ++f)
       FileBB[f] = f > FILE_A ? FileBB[f - 1] << 1 : FileABB;
@@ -173,14 +101,14 @@ void Bitboards::init() {
       AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0);
 
   for (Rank r = RANK_1; r < RANK_8; ++r)
-      InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]);
+      ForwardRanksBB[WHITE][r] = ~(ForwardRanksBB[BLACK][r + 1] = ForwardRanksBB[BLACK][r] | RankBB[r]);
 
   for (Color c = WHITE; c <= BLACK; ++c)
       for (Square s = SQ_A1; s <= SQ_H8; ++s)
       {
-          ForwardBB[c][s]      = InFrontBB[c][rank_of(s)] & FileBB[file_of(s)];
-          PawnAttackSpan[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];
-          PassedPawnMask[c][s] = ForwardBB[c][s] | PawnAttackSpan[c][s];
+          ForwardFileBB [c][s] = ForwardRanksBB[c][rank_of(s)] & FileBB[file_of(s)];
+          PawnAttackSpan[c][s] = ForwardRanksBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];
+          PassedPawnMask[c][s] = ForwardFileBB [c][s] | PawnAttackSpan[c][s];
       }
 
   for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
@@ -188,42 +116,46 @@ void Bitboards::init() {
           if (s1 != s2)
           {
               SquareDistance[s1][s2] = std::max(distance<File>(s1, s2), distance<Rank>(s1, s2));
-              DistanceRingBB[s1][SquareDistance[s1][s2] - 1] |= s2;
+              DistanceRingBB[s1][SquareDistance[s1][s2]] |= s2;
           }
 
-  int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },
-                     {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } };
+  int steps[][5] = { {}, { 7, 9 }, { 6, 10, 15, 17 }, {}, {}, {}, { 1, 7, 8, 9 } };
 
   for (Color c = WHITE; c <= BLACK; ++c)
-      for (PieceType pt = PAWN; pt <= KING; ++pt)
+      for (PieceType pt : { PAWN, KNIGHT, KING })
           for (Square s = SQ_A1; s <= SQ_H8; ++s)
               for (int i = 0; steps[pt][i]; ++i)
               {
-                  Square to = s + Square(c == WHITE ? steps[pt][i] : -steps[pt][i]);
+                  Square to = s + Direction(c == WHITE ? steps[pt][i] : -steps[pt][i]);
 
                   if (is_ok(to) && distance(s, to) < 3)
-                      StepAttacksBB[make_piece(c, pt)][s] |= to;
+                  {
+                      if (pt == PAWN)
+                          PawnAttacks[c][s] |= to;
+                      else
+                          PseudoAttacks[pt][s] |= to;
+                  }
               }
 
-  Square RookDeltas[] = { NORTH,  EAST,  SOUTH,  WEST  };
-  Square BishopDeltas[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
+  Direction RookDirections[] = { NORTH, EAST, SOUTH, WEST };
+  Direction BishopDirections[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
 
-  init_magics(RookTable, RookAttacks, RookMagics, RookMasks, RookShifts, RookDeltas, magic_index<ROOK>);
-  init_magics(BishopTable, BishopAttacks, BishopMagics, BishopMasks, BishopShifts, BishopDeltas, magic_index<BISHOP>);
+  init_magics(RookTable, RookMagics, RookDirections);
+  init_magics(BishopTable, BishopMagics, BishopDirections);
 
   for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
   {
       PseudoAttacks[QUEEN][s1]  = PseudoAttacks[BISHOP][s1] = attacks_bb<BISHOP>(s1, 0);
       PseudoAttacks[QUEEN][s1] |= PseudoAttacks[  ROOK][s1] = attacks_bb<  ROOK>(s1, 0);
 
-      for (Piece pc = W_BISHOP; pc <= W_ROOK; ++pc)
+      for (PieceType pt : { BISHOP, ROOK })
           for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
           {
-              if (!(PseudoAttacks[pc][s1] & s2))
+              if (!(PseudoAttacks[pt][s1] & s2))
                   continue;
 
-              LineBB[s1][s2] = (attacks_bb(pc, s1, 0) & attacks_bb(pc, s2, 0)) | s1 | s2;
-              BetweenBB[s1][s2] = attacks_bb(pc, s1, SquareBB[s2]) & attacks_bb(pc, s2, SquareBB[s1]);
+              LineBB[s1][s2] = (attacks_bb(pt, s1, 0) & attacks_bb(pt, s2, 0)) | s1 | s2;
+              BetweenBB[s1][s2] = attacks_bb(pt, s1, SquareBB[s2]) & attacks_bb(pt, s2, SquareBB[s1]);
           }
   }
 }
@@ -231,14 +163,14 @@ void Bitboards::init() {
 
 namespace {
 
-  Bitboard sliding_attack(Square deltas[], Square sq, Bitboard occupied) {
+  Bitboard sliding_attack(Direction directions[], Square sq, Bitboard occupied) {
 
     Bitboard attack = 0;
 
     for (int i = 0; i < 4; ++i)
-        for (Square s = sq + deltas[i];
-             is_ok(s) && distance(s, s - deltas[i]) == 1;
-             s += deltas[i])
+        for (Square s = sq + directions[i];
+             is_ok(s) && distance(s, s - directions[i]) == 1;
+             s += directions[i])
         {
             attack |= s;
 
@@ -255,17 +187,14 @@ namespace {
   // chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we
   // use the so called "fancy" approach.
 
-  void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
-                   Bitboard masks[], unsigned shifts[], Square deltas[], Fn index) {
+  void init_magics(Bitboard table[], Magic magics[], Direction directions[]) {
 
+    // Optimal PRNG seeds to pick the correct magics in the shortest time
     int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998,  5731, 95205, 104912, 17020 },
                              {  728, 10316, 55013, 32803, 12281, 15100,  16645,   255 } };
 
     Bitboard occupancy[4096], reference[4096], edges, b;
-    int age[4096] = {0}, current = 0, i, size;
-
-    // attacks[s] is a pointer to the beginning of the attacks table for square 's'
-    attacks[SQ_A1] = table;
+    int epoch[4096] = {}, cnt = 0, size = 0;
 
     for (Square s = SQ_A1; s <= SQ_H8; ++s)
     {
@@ -277,28 +206,28 @@ namespace {
         // all the attacks for each possible subset of the mask and so is 2 power
         // the number of 1s of the mask. Hence we deduce the size of the shift to
         // apply to the 64 or 32 bits word to get the index.
-        masks[s]  = sliding_attack(deltas, s, 0) & ~edges;
-        shifts[s] = (Is64Bit ? 64 : 32) - popcount(masks[s]);
+        Magic& m = magics[s];
+        m.mask  = sliding_attack(directions, s, 0) & ~edges;
+        m.shift = (Is64Bit ? 64 : 32) - popcount(m.mask);
+
+        // Set the offset for the attacks table of the square. We have individual
+        // table sizes for each square with "Fancy Magic Bitboards".
+        m.attacks = s == SQ_A1 ? table : magics[s - 1].attacks + size;
 
         // Use Carry-Rippler trick to enumerate all subsets of masks[s] and
         // store the corresponding sliding attack bitboard in reference[].
         b = size = 0;
         do {
             occupancy[size] = b;
-            reference[size] = sliding_attack(deltas, s, b);
+            reference[size] = sliding_attack(directions, s, b);
 
             if (HasPext)
-                attacks[s][pext(b, masks[s])] = reference[size];
+                m.attacks[pext(b, m.mask)] = reference[size];
 
             size++;
-            b = (b - masks[s]) & masks[s];
+            b = (b - m.mask) & m.mask;
         } while (b);
 
-        // Set the offset for the table of the next square. We have individual
-        // table sizes for each square with "Fancy Magic Bitboards".
-        if (s < SQ_H8)
-            attacks[s + 1] = attacks[s] + size;
-
         if (HasPext)
             continue;
 
@@ -306,28 +235,30 @@ namespace {
 
         // Find a magic for square 's' picking up an (almost) random number
         // until we find the one that passes the verification test.
-        do {
-            do
-                magics[s] = rng.sparse_rand<Bitboard>();
-            while (popcount((magics[s] * masks[s]) >> 56) < 6);
+        for (int i = 0; i < size; )
+        {
+            for (m.magic = 0; popcount((m.magic * m.mask) >> 56) < 6; )
+                m.magic = rng.sparse_rand<Bitboard>();
 
             // A good magic must map every possible occupancy to an index that
             // looks up the correct sliding attack in the attacks[s] database.
             // Note that we build up the database for square 's' as a side
-            // effect of verifying the magic.
-            for (++current, i = 0; i < size; ++i)
+            // effect of verifying the magic. Keep track of the attempt count
+            // and save it in epoch[], little speed-up trick to avoid resetting
+            // m.attacks[] after every failed attempt.
+            for (++cnt, i = 0; i < size; ++i)
             {
-                unsigned idx = index(s, occupancy[i]);
+                unsigned idx = m.index(occupancy[i]);
 
-                if (age[idx] < current)
+                if (epoch[idx] < cnt)
                 {
-                    age[idx] = current;
-                    attacks[s][idx] = reference[i];
+                    epoch[idx] = cnt;
+                    m.attacks[idx] = reference[i];
                 }
-                else if (attacks[s][idx] != reference[i])
+                else if (m.attacks[idx] != reference[i])
                     break;
             }
-        } while (i < size);
+        }
     }
   }
 }

src/bitboard.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -39,25 +39,26 @@ const std::string pretty(Bitboard b);
 
 }
 
-const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
+constexpr Bitboard AllSquares = ~Bitboard(0);
+constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
 
-const Bitboard FileABB = 0x0101010101010101ULL;
-const Bitboard FileBBB = FileABB << 1;
-const Bitboard FileCBB = FileABB << 2;
-const Bitboard FileDBB = FileABB << 3;
-const Bitboard FileEBB = FileABB << 4;
-const Bitboard FileFBB = FileABB << 5;
-const Bitboard FileGBB = FileABB << 6;
-const Bitboard FileHBB = FileABB << 7;
+constexpr Bitboard FileABB = 0x0101010101010101ULL;
+constexpr Bitboard FileBBB = FileABB << 1;
+constexpr Bitboard FileCBB = FileABB << 2;
+constexpr Bitboard FileDBB = FileABB << 3;
+constexpr Bitboard FileEBB = FileABB << 4;
+constexpr Bitboard FileFBB = FileABB << 5;
+constexpr Bitboard FileGBB = FileABB << 6;
+constexpr Bitboard FileHBB = FileABB << 7;
 
-const Bitboard Rank1BB = 0xFF;
-const Bitboard Rank2BB = Rank1BB << (8 * 1);
-const Bitboard Rank3BB = Rank1BB << (8 * 2);
-const Bitboard Rank4BB = Rank1BB << (8 * 3);
-const Bitboard Rank5BB = Rank1BB << (8 * 4);
-const Bitboard Rank6BB = Rank1BB << (8 * 5);
-const Bitboard Rank7BB = Rank1BB << (8 * 6);
-const Bitboard Rank8BB = Rank1BB << (8 * 7);
+constexpr Bitboard Rank1BB = 0xFF;
+constexpr Bitboard Rank2BB = Rank1BB << (8 * 1);
+constexpr Bitboard Rank3BB = Rank1BB << (8 * 2);
+constexpr Bitboard Rank4BB = Rank1BB << (8 * 3);
+constexpr Bitboard Rank5BB = Rank1BB << (8 * 4);
+constexpr Bitboard Rank6BB = Rank1BB << (8 * 5);
+constexpr Bitboard Rank7BB = Rank1BB << (8 * 6);
+constexpr Bitboard Rank8BB = Rank1BB << (8 * 7);
 
 extern int SquareDistance[SQUARE_NB][SQUARE_NB];
 
@@ -65,45 +66,75 @@ extern Bitboard SquareBB[SQUARE_NB];
 extern Bitboard FileBB[FILE_NB];
 extern Bitboard RankBB[RANK_NB];
 extern Bitboard AdjacentFilesBB[FILE_NB];
-extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
-extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
+extern Bitboard ForwardRanksBB[COLOR_NB][RANK_NB];
 extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
 extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
 extern Bitboard DistanceRingBB[SQUARE_NB][8];
-extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
+extern Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB];
 extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
 extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
 extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB];
+
+
+/// Magic holds all magic bitboards relevant data for a single square
+struct Magic {
+  Bitboard  mask;
+  Bitboard  magic;
+  Bitboard* attacks;
+  unsigned  shift;
+
+  // Compute the attack's index using the 'magic bitboards' approach
+  unsigned index(Bitboard occupied) const {
+
+    if (HasPext)
+        return unsigned(pext(occupied, mask));
+
+    if (Is64Bit)
+        return unsigned(((occupied & mask) * magic) >> shift);
+
+    unsigned lo = unsigned(occupied) & unsigned(mask);
+    unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
+    return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
+  }
+};
+
+extern Magic RookMagics[SQUARE_NB];
+extern Magic BishopMagics[SQUARE_NB];
 
 
 /// Overloads of bitwise operators between a Bitboard and a Square for testing
 /// whether a given bit is set in a bitboard, and for setting and clearing bits.
 
 inline Bitboard operator&(Bitboard b, Square s) {
+  assert(s >= SQ_A1 && s <= SQ_H8);
   return b & SquareBB[s];
 }
 
 inline Bitboard operator|(Bitboard b, Square s) {
+  assert(s >= SQ_A1 && s <= SQ_H8);
   return b | SquareBB[s];
 }
 
 inline Bitboard operator^(Bitboard b, Square s) {
+  assert(s >= SQ_A1 && s <= SQ_H8);
   return b ^ SquareBB[s];
 }
 
 inline Bitboard& operator|=(Bitboard& b, Square s) {
+  assert(s >= SQ_A1 && s <= SQ_H8);
   return b |= SquareBB[s];
 }
 
 inline Bitboard& operator^=(Bitboard& b, Square s) {
+  assert(s >= SQ_A1 && s <= SQ_H8);
   return b ^= SquareBB[s];
 }
 
-inline bool more_than_one(Bitboard b) {
+constexpr bool more_than_one(Bitboard b) {
   return b & (b - 1);
 }
 
-
 /// rank_bb() and file_bb() return a bitboard representing all the squares on
 /// the given file or rank.
 
@@ -124,17 +155,28 @@ inline Bitboard file_bb(Square s) {
 }
 
 
-/// shift() moves a bitboard one step along direction D. Mainly for pawns
+/// shift() moves a bitboard one step along direction D (mainly for pawns)
 
-template<Square D>
-inline Bitboard shift(Bitboard b) {
+template<Direction D>
+constexpr Bitboard shift(Bitboard b) {
   return  D == NORTH      ?  b             << 8 : D == SOUTH      ?  b             >> 8
-        : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == SOUTH_EAST ? (b & ~FileHBB) >> 7
-        : D == NORTH_WEST ? (b & ~FileABB) << 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9
+        : D == EAST       ? (b & ~FileHBB) << 1 : D == WEST       ? (b & ~FileABB) >> 1
+        : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == NORTH_WEST ? (b & ~FileABB) << 7
+        : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9
         : 0;
 }
 
 
+/// pawn_attacks_bb() returns the pawn attacks for the given color from the
+/// squares in the given bitboard.
+
+template<Color C>
+constexpr Bitboard pawn_attacks_bb(Bitboard b) {
+  return C == WHITE ? shift<NORTH_WEST>(b) | shift<NORTH_EAST>(b)
+                    : shift<SOUTH_WEST>(b) | shift<SOUTH_EAST>(b);
+}
+
+
 /// adjacent_files_bb() returns a bitboard representing all the squares on the
 /// adjacent files of the given one.
 
@@ -153,28 +195,28 @@ inline Bitboard between_bb(Square s1, Square s2) {
 }
 
 
-/// in_front_bb() returns a bitboard representing all the squares on all the ranks
-/// in front of the given one, from the point of view of the given color. For
-/// instance, in_front_bb(BLACK, RANK_3) will return the squares on ranks 1 and 2.
+/// forward_ranks_bb() returns a bitboard representing the squares on all the ranks
+/// in front of the given one, from the point of view of the given color. For instance,
+/// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2.
 
-inline Bitboard in_front_bb(Color c, Rank r) {
-  return InFrontBB[c][r];
+inline Bitboard forward_ranks_bb(Color c, Square s) {
+  return ForwardRanksBB[c][rank_of(s)];
 }
 
 
-/// forward_bb() returns a bitboard representing all the squares along the line
+/// forward_file_bb() returns a bitboard representing all the squares along the line
 /// in front of the given one, from the point of view of the given color:
-///        ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s)
+///      ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s)
 
-inline Bitboard forward_bb(Color c, Square s) {
-  return ForwardBB[c][s];
+inline Bitboard forward_file_bb(Color c, Square s) {
+  return ForwardFileBB[c][s];
 }
 
 
 /// pawn_attack_span() returns a bitboard representing all the squares that can be
 /// attacked by a pawn of the given color when it moves along its file, starting
 /// from the given square:
-///       PawnAttackSpan[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
+///      PawnAttackSpan[c][s] = forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s));
 
 inline Bitboard pawn_attack_span(Color c, Square s) {
   return PawnAttackSpan[c][s];
@@ -183,7 +225,7 @@ inline Bitboard pawn_attack_span(Color c, Square s) {
 
 /// passed_pawn_mask() returns a bitboard mask which can be used to test if a
 /// pawn of the given color and on the given square is a passed pawn:
-///       PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_bb(c, s)
+///      PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_file_bb(c, s)
 
 inline Bitboard passed_pawn_mask(Color c, Square s) {
   return PassedPawnMask[c][s];
@@ -210,50 +252,25 @@ template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_
 
 
 /// attacks_bb() returns a bitboard representing all the squares attacked by a
-/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index()
-/// looks up the index using the 'magic bitboards' approach.
-template<PieceType Pt>
-inline unsigned magic_index(Square s, Bitboard occupied) {
-
-  extern Bitboard RookMasks[SQUARE_NB];
-  extern Bitboard RookMagics[SQUARE_NB];
-  extern unsigned RookShifts[SQUARE_NB];
-  extern Bitboard BishopMasks[SQUARE_NB];
-  extern Bitboard BishopMagics[SQUARE_NB];
-  extern unsigned BishopShifts[SQUARE_NB];
-
-  Bitboard* const Masks  = Pt == ROOK ? RookMasks  : BishopMasks;
-  Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics;
-  unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts;
-
-  if (HasPext)
-      return unsigned(pext(occupied, Masks[s]));
-
-  if (Is64Bit)
-      return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]);
-
-  unsigned lo = unsigned(occupied) & unsigned(Masks[s]);
-  unsigned hi = unsigned(occupied >> 32) & unsigned(Masks[s] >> 32);
-  return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
-}
+/// piece of type Pt (bishop or rook) placed on 's'.
 
 template<PieceType Pt>
 inline Bitboard attacks_bb(Square s, Bitboard occupied) {
 
-  extern Bitboard* RookAttacks[SQUARE_NB];
-  extern Bitboard* BishopAttacks[SQUARE_NB];
-
-  return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index<Pt>(s, occupied)];
+  const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
+  return m.attacks[m.index(occupied)];
 }
 
-inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) {
+inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
 
-  switch (type_of(pc))
+  assert(pt != PAWN);
+
+  switch (pt)
   {
   case BISHOP: return attacks_bb<BISHOP>(s, occupied);
-  case ROOK  : return attacks_bb<ROOK>(s, occupied);
+  case ROOK  : return attacks_bb<  ROOK>(s, occupied);
   case QUEEN : return attacks_bb<BISHOP>(s, occupied) | attacks_bb<ROOK>(s, occupied);
-  default    : return StepAttacksBB[pc][s];
+  default    : return PseudoAttacks[pt][s];
   }
 }
 
@@ -282,7 +299,7 @@ inline int popcount(Bitboard b) {
 
 /// lsb() and msb() return the least/most significant bit in a non-zero bitboard
 
-#if defined(__GNUC__)
+#if defined(__GNUC__)  // GCC, Clang, ICC
 
 inline Square lsb(Bitboard b) {
   assert(b);
@@ -291,10 +308,12 @@ inline Square lsb(Bitboard b) {
 
 inline Square msb(Bitboard b) {
   assert(b);
-  return Square(63 - __builtin_clzll(b));
+  return Square(63 ^ __builtin_clzll(b));
 }
 
-#elif defined(_WIN64) && defined(_MSC_VER)
+#elif defined(_MSC_VER)  // MSVC
+
+#ifdef _WIN64  // MSVC, WIN64
 
 inline Square lsb(Bitboard b) {
   assert(b);
@@ -310,12 +329,39 @@ inline Square msb(Bitboard b) {
   return (Square) idx;
 }
 
-#else
+#else  // MSVC, WIN32
 
-#define NO_BSF // Fallback on software implementation for other cases
+inline Square lsb(Bitboard b) {
+  assert(b);
+  unsigned long idx;
 
-Square lsb(Bitboard b);
-Square msb(Bitboard b);
+  if (b & 0xffffffff) {
+      _BitScanForward(&idx, int32_t(b));
+      return Square(idx);
+  } else {
+      _BitScanForward(&idx, int32_t(b >> 32));
+      return Square(idx + 32);
+  }
+}
+
+inline Square msb(Bitboard b) {
+  assert(b);
+  unsigned long idx;
+
+  if (b >> 32) {
+      _BitScanReverse(&idx, int32_t(b >> 32));
+      return Square(idx + 32);
+  } else {
+      _BitScanReverse(&idx, int32_t(b));
+      return Square(idx);
+  }
+}
+
+#endif
+
+#else  // Compiler is neither GCC nor MSVC compatible
+
+#error "Compiler not supported."
 
 #endif
 

src/endgame.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,7 +31,7 @@ namespace {
 
   // Table used to drive the king towards the edge of the board
   // in KX vs K and KQ vs KR endgames.
-  const int PushToEdges[SQUARE_NB] = {
+  constexpr int PushToEdges[SQUARE_NB] = {
     100, 90, 80, 70, 70, 80, 90, 100,
      90, 70, 60, 50, 50, 60, 70,  90,
      80, 60, 40, 30, 30, 40, 60,  80,
@@ -44,7 +44,7 @@ namespace {
 
   // Table used to drive the king towards a corner square of the
   // right color in KBN vs K endgames.
-  const int PushToCorners[SQUARE_NB] = {
+  constexpr int PushToCorners[SQUARE_NB] = {
     200, 190, 180, 170, 160, 150, 140, 130,
     190, 180, 170, 160, 150, 140, 130, 140,
     180, 170, 155, 140, 140, 125, 140, 150,
@@ -56,11 +56,11 @@ namespace {
   };
 
   // Tables used to drive a piece towards or away from another piece
-  const int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 };
-  const int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 };
+  constexpr int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 };
+  constexpr int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 };
 
   // Pawn Rank based scaling factors used in KRPPKRP endgame
-  const int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 };
+  constexpr int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 };
 
 #ifndef NDEBUG
   bool verify_material(const Position& pos, Color c, Value npm, int pawnsCnt) {
@@ -83,60 +83,9 @@ namespace {
     return sq;
   }
 
-  // Get the material key of Position out of the given endgame key code
-  // like "KBPKN". The trick here is to first forge an ad-hoc FEN string
-  // and then let a Position object do the work for us.
-  Key key(const string& code, Color c) {
-
-    assert(code.length() > 0 && code.length() < 8);
-    assert(code[0] == 'K');
-
-    string sides[] = { code.substr(code.find('K', 1)),      // Weak
-                       code.substr(0, code.find('K', 1)) }; // Strong
-
-    std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
-
-    string fen =  sides[0] + char(8 - sides[0].length() + '0') + "/8/8/8/8/8/8/"
-                + sides[1] + char(8 - sides[1].length() + '0') + " w - - 0 10";
-
-    StateInfo st;
-    return Position().set(fen, false, &st, nullptr).material_key();
-  }
-
 } // namespace
 
 
-/// Endgames members definitions
-
-Endgames::Endgames() {
-
-  add<KPK>("KPK");
-  add<KNNK>("KNNK");
-  add<KBNK>("KBNK");
-  add<KRKP>("KRKP");
-  add<KRKB>("KRKB");
-  add<KRKN>("KRKN");
-  add<KQKP>("KQKP");
-  add<KQKR>("KQKR");
-
-  add<KNPK>("KNPK");
-  add<KNPKB>("KNPKB");
-  add<KRPKR>("KRPKR");
-  add<KRPKB>("KRPKB");
-  add<KBPKB>("KBPKB");
-  add<KBPKN>("KBPKN");
-  add<KBPPKB>("KBPPKB");
-  add<KRPPKRP>("KRPPKRP");
-}
-
-
-template<EndgameType E, typename T>
-void Endgames::add(const string& code) {
-  map<T>()[key(code, WHITE)] = std::unique_ptr<EndgameBase<T>>(new Endgame<E>(WHITE));
-  map<T>()[key(code, BLACK)] = std::unique_ptr<EndgameBase<T>>(new Endgame<E>(BLACK));
-}
-
-
 /// Mate with KX vs K. This function is used to evaluate positions with
 /// king and plenty of material vs a lone king. It simply gives the
 /// attacking side a bonus for driving the defending king towards the edge
@@ -162,8 +111,8 @@ Value Endgame<KXK>::operator()(const Position& pos) const {
   if (   pos.count<QUEEN>(strongSide)
       || pos.count<ROOK>(strongSide)
       ||(pos.count<BISHOP>(strongSide) && pos.count<KNIGHT>(strongSide))
-      ||(pos.count<BISHOP>(strongSide) > 1 && opposite_colors(pos.squares<BISHOP>(strongSide)[0],
-                                                              pos.squares<BISHOP>(strongSide)[1])))
+      || (   (pos.pieces(strongSide, BISHOP) & ~DarkSquares)
+          && (pos.pieces(strongSide, BISHOP) &  DarkSquares)))
       result = std::min(result + VALUE_KNOWN_WIN, VALUE_MATE_IN_MAX_PLY - 1);
 
   return strongSide == pos.side_to_move() ? result : -result;
@@ -241,7 +190,7 @@ Value Endgame<KRKP>::operator()(const Position& pos) const {
   Value result;
 
   // If the stronger side's king is in front of the pawn, it's a win
-  if (wksq < psq && file_of(wksq) == file_of(psq))
+  if (forward_file_bb(WHITE, wksq) & psq)
       result = RookValueEg - distance(wksq, psq);
 
   // If the weaker side's king is too far from the pawn and the rook,
@@ -267,7 +216,7 @@ Value Endgame<KRKP>::operator()(const Position& pos) const {
 }
 
 
-/// KR vs KB. This is very simple, and always returns drawish scores.  The
+/// KR vs KB. This is very simple, and always returns drawish scores. The
 /// score is slightly bigger when the defending king is close to the edge.
 template<>
 Value Endgame<KRKB>::operator()(const Position& pos) const {
@@ -551,7 +500,7 @@ ScaleFactor Endgame<KRPKB>::operator()(const Position& pos) const {
       Square bsq = pos.square<BISHOP>(weakSide);
       Square psq = pos.square<PAWN>(strongSide);
       Rank rk = relative_rank(strongSide, psq);
-      Square push = pawn_push(strongSide);
+      Direction push = pawn_push(strongSide);
 
       // If the pawn is on the 5th rank and the pawn (currently) is on
       // the same color square as the bishop then there is a chance of
@@ -625,7 +574,7 @@ ScaleFactor Endgame<KPsK>::operator()(const Position& pos) const {
 
   // If all pawns are ahead of the king, on a single rook file and
   // the king is within one file of the pawns, it's a draw.
-  if (   !(pawns & ~in_front_bb(weakSide, rank_of(ksq)))
+  if (   !(pawns & ~forward_ranks_bb(weakSide, ksq))
       && !((pawns & ~FileABB) && (pawns & ~FileHBB))
       &&  distance<File>(ksq, lsb(pawns)) <= 1)
       return SCALE_FACTOR_DRAW;
@@ -658,31 +607,8 @@ ScaleFactor Endgame<KBPKB>::operator()(const Position& pos) const {
 
   // Case 2: Opposite colored bishops
   if (opposite_colors(strongBishopSq, weakBishopSq))
-  {
-      // We assume that the position is drawn in the following three situations:
-      //
-      //   a. The pawn is on rank 5 or further back.
-      //   b. The defending king is somewhere in the pawn's path.
-      //   c. The defending bishop attacks some square along the pawn's path,
-      //      and is at least three squares away from the pawn.
-      //
-      // These rules are probably not perfect, but in practice they work
-      // reasonably well.
+      return SCALE_FACTOR_DRAW;
 
-      if (relative_rank(strongSide, pawnSq) <= RANK_5)
-          return SCALE_FACTOR_DRAW;
-      else
-      {
-          Bitboard path = forward_bb(strongSide, pawnSq);
-
-          if (path & pos.pieces(weakSide, KING))
-              return SCALE_FACTOR_DRAW;
-
-          if (  (pos.attacks_from<BISHOP>(weakBishopSq) & path)
-              && distance(weakBishopSq, pawnSq) >= 3)
-              return SCALE_FACTOR_DRAW;
-      }
-  }
   return SCALE_FACTOR_NONE;
 }
 
@@ -809,7 +735,7 @@ ScaleFactor Endgame<KNPKB>::operator()(const Position& pos) const {
 
   // King needs to get close to promoting pawn to prevent knight from blocking.
   // Rules for this are very tricky, so just approximate.
-  if (forward_bb(strongSide, pawnSq) & pos.attacks_from<BISHOP>(bishopSq))
+  if (forward_file_bb(strongSide, pawnSq) & pos.attacks_from<BISHOP>(bishopSq))
       return ScaleFactor(distance(weakKingSq, pawnSq));
 
   return SCALE_FACTOR_NONE;

src/endgame.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,12 +31,11 @@
 #include "types.h"
 
 
-/// EndgameType lists all supported endgames
+/// EndgameCode lists all supported endgame functions by corresponding codes
 
-enum EndgameType {
-
-  // Evaluation functions
+enum EndgameCode {
 
+  EVALUATION_FUNCTIONS,
   KNNK,  // KNN vs K
   KXK,   // Generic "mate lone king" eval
   KBNK,  // KBN vs K
@@ -47,10 +46,7 @@ enum EndgameType {
   KQKP,  // KQ vs KP
   KQKR,  // KQ vs KR
 
-
-  // Scaling functions
   SCALING_FUNCTIONS,
-
   KBPsK,   // KB and pawns vs K
   KQKRPs,  // KQ vs KR and pawns
   KRPKR,   // KRP vs KR
@@ -68,30 +64,29 @@ enum EndgameType {
 
 /// Endgame functions can be of two types depending on whether they return a
 /// Value or a ScaleFactor.
-template<EndgameType E> using
+
+template<EndgameCode E> using
 eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type;
 
 
-/// Base and derived templates for endgame evaluation and scaling functions
+/// Base and derived functors for endgame evaluation and scaling functions
 
 template<typename T>
 struct EndgameBase {
 
+  explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {}
   virtual ~EndgameBase() = default;
-  virtual Color strong_side() const = 0;
   virtual T operator()(const Position&) const = 0;
+
+  const Color strongSide, weakSide;
 };
 
 
-template<EndgameType E, typename T = eg_type<E>>
+template<EndgameCode E, typename T = eg_type<E>>
 struct Endgame : public EndgameBase<T> {
 
-  explicit Endgame(Color c) : strongSide(c), weakSide(~c) {}
-  Color strong_side() const { return strongSide; }
-  T operator()(const Position&) const;
-
-private:
-  Color strongSide, weakSide;
+  explicit Endgame(Color c) : EndgameBase<T>(c) {}
+  T operator()(const Position&) const override;
 };
 
 
@@ -101,23 +96,48 @@ private:
 
 class Endgames {
 
-  template<typename T> using Map = std::map<Key, std::unique_ptr<EndgameBase<T>>>;
-
-  template<EndgameType E, typename T = eg_type<E>>
-  void add(const std::string& code);
+  template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
+  template<typename T> using Map = std::map<Key, Ptr<T>>;
 
   template<typename T>
   Map<T>& map() {
     return std::get<std::is_same<T, ScaleFactor>::value>(maps);
   }
 
+  template<EndgameCode E, typename T = eg_type<E>>
+  void add(const std::string& code) {
+
+    StateInfo st;
+    map<T>()[Position().set(code, WHITE, &st).material_key()] = Ptr<T>(new Endgame<E>(WHITE));
+    map<T>()[Position().set(code, BLACK, &st).material_key()] = Ptr<T>(new Endgame<E>(BLACK));
+  }
+
   std::pair<Map<Value>, Map<ScaleFactor>> maps;
 
 public:
-  Endgames();
+  Endgames() {
+
+    add<KPK>("KPK");
+    add<KNNK>("KNNK");
+    add<KBNK>("KBNK");
+    add<KRKP>("KRKP");
+    add<KRKB>("KRKB");
+    add<KRKN>("KRKN");
+    add<KQKP>("KQKP");
+    add<KQKR>("KQKR");
+
+    add<KNPK>("KNPK");
+    add<KNPKB>("KNPKB");
+    add<KRPKR>("KRPKR");
+    add<KRPKB>("KRPKB");
+    add<KBPKB>("KBPKB");
+    add<KBPKN>("KBPKN");
+    add<KBPPKB>("KBPPKB");
+    add<KRPPKRP>("KRPPKRP");
+  }
 
   template<typename T>
-  EndgameBase<T>* probe(Key key) {
+  const EndgameBase<T>* probe(Key key) {
     return map<T>().count(key) ? map<T>()[key].get() : nullptr;
   }
 };

src/evaluate.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -29,11 +29,10 @@ class Position;
 
 namespace Eval {
 
-const Value Tempo = Value(20); // Must be visible to search
+constexpr Value Tempo = Value(20); // Must be visible to search
 
 std::string trace(const Position& pos);
 
-template<bool DoTrace = false>
 Value evaluate(const Position& pos);
 }
 

src/main.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -43,12 +43,11 @@ int main(int argc, char* argv[]) {
   Bitbases::init();
   Search::init();
   Pawns::init();
-  Threads.init();
-  Tablebases::init(Options["SyzygyPath"]);
-  TT.resize(Options["Hash"]);
+  Threads.set(Options["Threads"]);
+  Search::clear(); // After threads are up
 
   UCI::loop(argc, argv);
 
-  Threads.exit();
+  Threads.set(0);
   return 0;
 }

src/material.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,18 +31,18 @@ namespace {
 
   // Polynomial material imbalance parameters
 
-  const int QuadraticOurs[][PIECE_TYPE_NB] = {
+  constexpr int QuadraticOurs[][PIECE_TYPE_NB] = {
     //            OUR PIECES
     // pair pawn knight bishop rook queen
-    {1667                               }, // Bishop pair
-    {  40,    2                         }, // Pawn
-    {  32,  255,  -3                    }, // Knight      OUR PIECES
+    {1438                               }, // Bishop pair
+    {  40,   38                         }, // Pawn
+    {  32,  255, -62                    }, // Knight      OUR PIECES
     {   0,  104,   4,    0              }, // Bishop
-    { -26,   -2,  47,   105,  -149      }, // Rook
-    {-185,   24, 122,   137,  -134,   0 }  // Queen
+    { -26,   -2,  47,   105,  -208      }, // Rook
+    {-189,   24, 117,   133,  -134, -6  }  // Queen
   };
 
-  const int QuadraticTheirs[][PIECE_TYPE_NB] = {
+  constexpr int QuadraticTheirs[][PIECE_TYPE_NB] = {
     //           THEIR PIECES
     // pair pawn knight bishop rook queen
     {   0                               }, // Bishop pair
@@ -50,7 +50,7 @@ namespace {
     {   9,   63,   0                    }, // Knight      OUR PIECES
     {  59,   65,  42,     0             }, // Bishop
     {  46,   39,  24,   -24,    0       }, // Rook
-    { 101,  100, -37,   141,  268,    0 }  // Queen
+    {  97,  100, -42,   137,  268,    0 }  // Queen
   };
 
   // Endgame evaluation and scaling functions are accessed directly and not through
@@ -68,7 +68,7 @@ namespace {
           && pos.non_pawn_material(us) >= RookValueMg;
   }
 
-  bool is_KBPsKs(const Position& pos, Color us) {
+  bool is_KBPsK(const Position& pos, Color us) {
     return   pos.non_pawn_material(us) == BishopValueMg
           && pos.count<BISHOP>(us) == 1
           && pos.count<PAWN  >(us) >= 1;
@@ -77,7 +77,7 @@ namespace {
   bool is_KQKRPs(const Position& pos, Color us) {
     return  !pos.count<PAWN>(us)
           && pos.non_pawn_material(us) == QueenValueMg
-          && pos.count<QUEEN>(us)  == 1
+          && pos.count<QUEEN>(us) == 1
           && pos.count<ROOK>(~us) == 1
           && pos.count<PAWN>(~us) >= 1;
   }
@@ -87,11 +87,11 @@ namespace {
   template<Color Us>
   int imbalance(const int pieceCount[][PIECE_TYPE_NB]) {
 
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
 
     int bonus = 0;
 
-    // Second-degree polynomial material imbalance by Tord Romstad
+    // Second-degree polynomial material imbalance, by Tord Romstad
     for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
     {
         if (!pieceCount[Us][pt1])
@@ -129,7 +129,13 @@ Entry* probe(const Position& pos) {
   std::memset(e, 0, sizeof(Entry));
   e->key = key;
   e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;
-  e->gamePhase = pos.game_phase();
+
+  Value npm_w = pos.non_pawn_material(WHITE);
+  Value npm_b = pos.non_pawn_material(BLACK);
+  Value npm = std::max(EndgameLimit, std::min(npm_w + npm_b, MidgameLimit));
+
+  // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]
+  e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));
 
   // Let's look if we have a specialized evaluation function for this particular
   // material configuration. Firstly we look for a fixed configuration one, then
@@ -146,11 +152,11 @@ Entry* probe(const Position& pos) {
 
   // OK, we didn't find any special evaluation function for the current material
   // configuration. Is there a suitable specialized scaling function?
-  EndgameBase<ScaleFactor>* sf;
+  const EndgameBase<ScaleFactor>* sf;
 
   if ((sf = pos.this_thread()->endgames.probe<ScaleFactor>(key)) != nullptr)
   {
-      e->scalingFunction[sf->strong_side()] = sf; // Only strong color assigned
+      e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned
       return e;
   }
 
@@ -159,16 +165,13 @@ Entry* probe(const Position& pos) {
   // case we don't return after setting the function.
   for (Color c = WHITE; c <= BLACK; ++c)
   {
-    if (is_KBPsKs(pos, c))
+    if (is_KBPsK(pos, c))
         e->scalingFunction[c] = &ScaleKBPsK[c];
 
     else if (is_KQKRPs(pos, c))
         e->scalingFunction[c] = &ScaleKQKRPs[c];
   }
 
-  Value npm_w = pos.non_pawn_material(WHITE);
-  Value npm_b = pos.non_pawn_material(BLACK);
-
   if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board
   {
       if (!pos.count<PAWN>(BLACK))
@@ -203,22 +206,16 @@ Entry* probe(const Position& pos) {
       e->factor[BLACK] = uint8_t(npm_b <  RookValueMg   ? SCALE_FACTOR_DRAW :
                                  npm_w <= BishopValueMg ? 4 : 14);
 
-  if (pos.count<PAWN>(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)
-      e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN;
-
-  if (pos.count<PAWN>(BLACK) == 1 && npm_b - npm_w <= BishopValueMg)
-      e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN;
-
   // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder
   // for the bishop pair "extended piece", which allows us to be more flexible
   // in defining bishop pair bonuses.
-  const int PieceCount[COLOR_NB][PIECE_TYPE_NB] = {
+  const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = {
   { pos.count<BISHOP>(WHITE) > 1, pos.count<PAWN>(WHITE), pos.count<KNIGHT>(WHITE),
     pos.count<BISHOP>(WHITE)    , pos.count<ROOK>(WHITE), pos.count<QUEEN >(WHITE) },
   { pos.count<BISHOP>(BLACK) > 1, pos.count<PAWN>(BLACK), pos.count<KNIGHT>(BLACK),
     pos.count<BISHOP>(BLACK)    , pos.count<ROOK>(BLACK), pos.count<QUEEN >(BLACK) } };
 
-  e->value = int16_t((imbalance<WHITE>(PieceCount) - imbalance<BLACK>(PieceCount)) / 16);
+  e->value = int16_t((imbalance<WHITE>(pieceCount) - imbalance<BLACK>(pieceCount)) / 16);
   return e;
 }
 

src/material.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -56,11 +56,11 @@ struct Entry {
   }
 
   Key key;
+  const EndgameBase<Value>* evaluationFunction;
+  const EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB]; // Could be one for each
+                                                             // side (e.g. KPKP, KBPsKs)
   int16_t value;
   uint8_t factor[COLOR_NB];
-  EndgameBase<Value>* evaluationFunction;
-  EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB]; // Could be one for each
-                                                       // side (e.g. KPKP, KBPsKs)
   Phase gamePhase;
 };
 

src/misc.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -18,10 +18,34 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#ifdef _WIN32
+#if _WIN32_WINNT < 0x0601
+#undef  _WIN32_WINNT
+#define _WIN32_WINNT 0x0601 // Force to include needed API prototypes
+#endif
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+
+#include <windows.h>
+// The needed Windows API for processor groups could be missed from old Windows
+// versions, so instead of calling them directly (forcing the linker to resolve
+// the calls at compile time), try to load them at runtime. To do this we need
+// first to define the corresponding function pointers.
+extern "C" {
+typedef bool(*fun1_t)(LOGICAL_PROCESSOR_RELATIONSHIP,
+                      PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD);
+typedef bool(*fun2_t)(USHORT, PGROUP_AFFINITY);
+typedef bool(*fun3_t)(HANDLE, CONST GROUP_AFFINITY*, PGROUP_AFFINITY);
+}
+#endif
+
 #include <fstream>
 #include <iomanip>
 #include <iostream>
 #include <sstream>
+#include <vector>
 
 #include "misc.h"
 #include "thread.h"
@@ -32,7 +56,7 @@ namespace {
 
 /// Version number. If Version is left empty, then compile date in the format
 /// DD-MM-YY and show in engine_info.
-const string Version = "8";
+const string Version = "10";
 
 /// Our fancy logging facility. The trick here is to replace cin.rdbuf() and
 /// cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We
@@ -44,10 +68,10 @@ struct Tie: public streambuf { // MSVC requires split streambuf for cin and cout
 
   Tie(streambuf* b, streambuf* l) : buf(b), logBuf(l) {}
 
-  int sync() { return logBuf->pubsync(), buf->pubsync(); }
-  int overflow(int c) { return log(buf->sputc((char)c), "<< "); }
-  int underflow() { return buf->sgetc(); }
-  int uflow() { return log(buf->sbumpc(), ">> "); }
+  int sync() override { return logBuf->pubsync(), buf->pubsync(); }
+  int overflow(int c) override { return log(buf->sputc((char)c), "<< "); }
+  int underflow() override { return buf->sgetc(); }
+  int uflow() override { return log(buf->sbumpc(), ">> "); }
 
   streambuf *buf, *logBuf;
 
@@ -185,3 +209,114 @@ void prefetch(void* addr) {
 }
 
 #endif
+
+void prefetch2(void* addr) {
+
+  prefetch(addr);
+  prefetch((uint8_t*)addr + 64);
+}
+
+namespace WinProcGroup {
+
+#ifndef _WIN32
+
+void bindThisThread(size_t) {}
+
+#else
+
+/// best_group() retrieves logical processor information using Windows specific
+/// API and returns the best group id for the thread with index idx. Original
+/// code from Texel by Peter Österlund.
+
+int best_group(size_t idx) {
+
+  int threads = 0;
+  int nodes = 0;
+  int cores = 0;
+  DWORD returnLength = 0;
+  DWORD byteOffset = 0;
+
+  // Early exit if the needed API is not available at runtime
+  HMODULE k32 = GetModuleHandle("Kernel32.dll");
+  auto fun1 = (fun1_t)(void(*)())GetProcAddress(k32, "GetLogicalProcessorInformationEx");
+  if (!fun1)
+      return -1;
+
+  // First call to get returnLength. We expect it to fail due to null buffer
+  if (fun1(RelationAll, nullptr, &returnLength))
+      return -1;
+
+  // Once we know returnLength, allocate the buffer
+  SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *buffer, *ptr;
+  ptr = buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX*)malloc(returnLength);
+
+  // Second call, now we expect to succeed
+  if (!fun1(RelationAll, buffer, &returnLength))
+  {
+      free(buffer);
+      return -1;
+  }
+
+  while (ptr->Size > 0 && byteOffset + ptr->Size <= returnLength)
+  {
+      if (ptr->Relationship == RelationNumaNode)
+          nodes++;
+
+      else if (ptr->Relationship == RelationProcessorCore)
+      {
+          cores++;
+          threads += (ptr->Processor.Flags == LTP_PC_SMT) ? 2 : 1;
+      }
+
+      byteOffset += ptr->Size;
+      ptr = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX*)(((char*)ptr) + ptr->Size);
+  }
+
+  free(buffer);
+
+  std::vector<int> groups;
+
+  // Run as many threads as possible on the same node until core limit is
+  // reached, then move on filling the next node.
+  for (int n = 0; n < nodes; n++)
+      for (int i = 0; i < cores / nodes; i++)
+          groups.push_back(n);
+
+  // In case a core has more than one logical processor (we assume 2) and we
+  // have still threads to allocate, then spread them evenly across available
+  // nodes.
+  for (int t = 0; t < threads - cores; t++)
+      groups.push_back(t % nodes);
+
+  // If we still have more threads than the total number of logical processors
+  // then return -1 and let the OS to decide what to do.
+  return idx < groups.size() ? groups[idx] : -1;
+}
+
+
+/// bindThisThread() set the group affinity of the current thread
+
+void bindThisThread(size_t idx) {
+
+  // Use only local variables to be thread-safe
+  int group = best_group(idx);
+
+  if (group == -1)
+      return;
+
+  // Early exit if the needed API are not available at runtime
+  HMODULE k32 = GetModuleHandle("Kernel32.dll");
+  auto fun2 = (fun2_t)(void(*)())GetProcAddress(k32, "GetNumaNodeProcessorMaskEx");
+  auto fun3 = (fun3_t)(void(*)())GetProcAddress(k32, "SetThreadGroupAffinity");
+
+  if (!fun2 || !fun3)
+      return;
+
+  GROUP_AFFINITY affinity;
+  if (fun2(group, &affinity))
+      fun3(GetCurrentThread(), &affinity, nullptr);
+}
+
+#endif
+
+} // namespace WinProcGroup

src/misc.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,6 +31,7 @@
 
 const std::string engine_info(bool to_uci = false);
 void prefetch(void* addr);
+void prefetch2(void* addr);
 void start_logger(const std::string& fname);
 
 void dbg_hit_on(bool b);
@@ -40,6 +41,8 @@ void dbg_print();
 
 typedef std::chrono::milliseconds::rep TimePoint; // A value in milliseconds
 
+static_assert(sizeof(TimePoint) == sizeof(int64_t), "TimePoint should be 64 bits");
+
 inline TimePoint now() {
   return std::chrono::duration_cast<std::chrono::milliseconds>
         (std::chrono::steady_clock::now().time_since_epoch()).count();
@@ -97,4 +100,15 @@ public:
   { return T(rand64() & rand64() & rand64()); }
 };
 
+
+/// Under Windows it is not possible for a process to run on more than one
+/// logical processor group. This usually means to be limited to use max 64
+/// cores. To overcome this, some special platform specific API should be
+/// called to set group affinity for each thread. Original code from Texel by
+/// Peter Österlund.
+
+namespace WinProcGroup {
+  void bindThisThread(size_t idx);
+}
+
 #endif // #ifndef MISC_H_INCLUDED

src/movegen.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -25,34 +25,35 @@
 
 namespace {
 
-  template<CastlingRight Cr, bool Checks, bool Chess960>
-  ExtMove* generate_castling(const Position& pos, ExtMove* moveList, Color us) {
+  template<Color Us, CastlingSide Cs, bool Checks, bool Chess960>
+  ExtMove* generate_castling(const Position& pos, ExtMove* moveList) {
 
-    static const bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO);
+    constexpr CastlingRight Cr = Us | Cs;
+    constexpr bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO);
 
     if (pos.castling_impeded(Cr) || !pos.can_castle(Cr))
         return moveList;
 
     // After castling, the rook and king final positions are the same in Chess960
     // as they would be in standard chess.
-    Square kfrom = pos.square<KING>(us);
+    Square kfrom = pos.square<KING>(Us);
     Square rfrom = pos.castling_rook_square(Cr);
-    Square kto = relative_square(us, KingSide ? SQ_G1 : SQ_C1);
-    Bitboard enemies = pos.pieces(~us);
+    Square kto = relative_square(Us, KingSide ? SQ_G1 : SQ_C1);
+    Bitboard enemies = pos.pieces(~Us);
 
     assert(!pos.checkers());
 
-    const Square K = Chess960 ? kto > kfrom ? WEST : EAST
-                              : KingSide    ? WEST : EAST;
+    const Direction step = Chess960 ? kto > kfrom ? WEST : EAST
+                                    : KingSide    ? WEST : EAST;
 
-    for (Square s = kto; s != kfrom; s += K)
+    for (Square s = kto; s != kfrom; s += step)
         if (pos.attackers_to(s) & enemies)
             return moveList;
 
     // Because we generate only legal castling moves we need to verify that
     // when moving the castling rook we do not discover some hidden checker.
     // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
-    if (Chess960 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN)))
+    if (Chess960 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~Us, ROOK, QUEEN)))
         return moveList;
 
     Move m = make<CASTLING>(kfrom, rfrom);
@@ -65,7 +66,7 @@ namespace {
   }
 
 
-  template<GenType Type, Square D>
+  template<GenType Type, Direction D>
   ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) {
 
     if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
@@ -80,7 +81,7 @@ namespace {
 
     // Knight promotion is the only promotion that can give a direct check
     // that's not already included in the queen promotion.
-    if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ksq))
+    if (Type == QUIET_CHECKS && (PseudoAttacks[KNIGHT][to] & ksq))
         *moveList++ = make<PROMOTION>(to - D, to, KNIGHT);
     else
         (void)ksq; // Silence a warning under MSVC
@@ -94,13 +95,13 @@ namespace {
 
     // Compute our parametrized parameters at compile time, named according to
     // the point of view of white side.
-    const Color    Them     = (Us == WHITE ? BLACK      : WHITE);
-    const Bitboard TRank8BB = (Us == WHITE ? Rank8BB    : Rank1BB);
-    const Bitboard TRank7BB = (Us == WHITE ? Rank7BB    : Rank2BB);
-    const Bitboard TRank3BB = (Us == WHITE ? Rank3BB    : Rank6BB);
-    const Square   Up       = (Us == WHITE ? NORTH      : SOUTH);
-    const Square   Right    = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Square   Left     = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+    constexpr Color     Them     = (Us == WHITE ? BLACK      : WHITE);
+    constexpr Bitboard  TRank8BB = (Us == WHITE ? Rank8BB    : Rank1BB);
+    constexpr Bitboard  TRank7BB = (Us == WHITE ? Rank7BB    : Rank2BB);
+    constexpr Bitboard  TRank3BB = (Us == WHITE ? Rank3BB    : Rank6BB);
+    constexpr Direction Up       = (Us == WHITE ? NORTH      : SOUTH);
+    constexpr Direction UpRight  = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+    constexpr Direction UpLeft   = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
 
     Bitboard emptySquares;
 
@@ -135,7 +136,7 @@ namespace {
             // if the pawn is not on the same file as the enemy king, because we
             // don't generate captures. Note that a possible discovery check
             // promotion has been already generated amongst the captures.
-            Bitboard dcCandidates = pos.discovered_check_candidates();
+            Bitboard dcCandidates = pos.blockers_for_king(Them);
             if (pawnsNotOn7 & dcCandidates)
             {
                 Bitboard dc1 = shift<Up>(pawnsNotOn7 & dcCandidates) & emptySquares & ~file_bb(ksq);
@@ -168,38 +169,38 @@ namespace {
         if (Type == EVASIONS)
             emptySquares &= target;
 
-        Bitboard b1 = shift<Right>(pawnsOn7) & enemies;
-        Bitboard b2 = shift<Left >(pawnsOn7) & enemies;
-        Bitboard b3 = shift<Up   >(pawnsOn7) & emptySquares;
+        Bitboard b1 = shift<UpRight>(pawnsOn7) & enemies;
+        Bitboard b2 = shift<UpLeft >(pawnsOn7) & enemies;
+        Bitboard b3 = shift<Up     >(pawnsOn7) & emptySquares;
 
         Square ksq = pos.square<KING>(Them);
 
         while (b1)
-            moveList = make_promotions<Type, Right>(moveList, pop_lsb(&b1), ksq);
+            moveList = make_promotions<Type, UpRight>(moveList, pop_lsb(&b1), ksq);
 
         while (b2)
-            moveList = make_promotions<Type, Left >(moveList, pop_lsb(&b2), ksq);
+            moveList = make_promotions<Type, UpLeft >(moveList, pop_lsb(&b2), ksq);
 
         while (b3)
-            moveList = make_promotions<Type, Up   >(moveList, pop_lsb(&b3), ksq);
+            moveList = make_promotions<Type, Up     >(moveList, pop_lsb(&b3), ksq);
     }
 
     // Standard and en-passant captures
     if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
     {
-        Bitboard b1 = shift<Right>(pawnsNotOn7) & enemies;
-        Bitboard b2 = shift<Left >(pawnsNotOn7) & enemies;
+        Bitboard b1 = shift<UpRight>(pawnsNotOn7) & enemies;
+        Bitboard b2 = shift<UpLeft >(pawnsNotOn7) & enemies;
 
         while (b1)
         {
             Square to = pop_lsb(&b1);
-            *moveList++ = make_move(to - Right, to);
+            *moveList++ = make_move(to - UpRight, to);
         }
 
         while (b2)
         {
             Square to = pop_lsb(&b2);
-            *moveList++ = make_move(to - Left, to);
+            *moveList++ = make_move(to - UpLeft, to);
         }
 
         if (pos.ep_square() != SQ_NONE)
@@ -241,7 +242,7 @@ namespace {
                 && !(PseudoAttacks[Pt][from] & target & pos.check_squares(Pt)))
                 continue;
 
-            if (pos.discovered_check_candidates() & from)
+            if (pos.blockers_for_king(~us) & from)
                 continue;
         }
 
@@ -261,7 +262,7 @@ namespace {
   template<Color Us, GenType Type>
   ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) {
 
-    const bool Checks = Type == QUIET_CHECKS;
+    constexpr bool Checks = Type == QUIET_CHECKS;
 
     moveList = generate_pawn_moves<Us, Type>(pos, moveList, target);
     moveList = generate_moves<KNIGHT, Checks>(pos, moveList, Us, target);
@@ -281,13 +282,13 @@ namespace {
     {
         if (pos.is_chess960())
         {
-            moveList = generate_castling<MakeCastling<Us,  KING_SIDE>::right, Checks, true>(pos, moveList, Us);
-            moveList = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, true>(pos, moveList, Us);
+            moveList = generate_castling<Us, KING_SIDE, Checks, true>(pos, moveList);
+            moveList = generate_castling<Us, QUEEN_SIDE, Checks, true>(pos, moveList);
         }
         else
         {
-            moveList = generate_castling<MakeCastling<Us,  KING_SIDE>::right, Checks, false>(pos, moveList, Us);
-            moveList = generate_castling<MakeCastling<Us, QUEEN_SIDE>::right, Checks, false>(pos, moveList, Us);
+            moveList = generate_castling<Us, KING_SIDE, Checks, false>(pos, moveList);
+            moveList = generate_castling<Us, QUEEN_SIDE, Checks, false>(pos, moveList);
         }
     }
 
@@ -336,7 +337,7 @@ ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
   assert(!pos.checkers());
 
   Color us = pos.side_to_move();
-  Bitboard dc = pos.discovered_check_candidates();
+  Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us);
 
   while (dc)
   {
@@ -346,7 +347,7 @@ ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* moveList) {
      if (pt == PAWN)
          continue; // Will be generated together with direct checks
 
-     Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces();
+     Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces();
 
      if (pt == KING)
          b &= ~PseudoAttacks[QUEEN][pos.square<KING>(~us)];
@@ -403,8 +404,9 @@ ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* moveList) {
 template<>
 ExtMove* generate<LEGAL>(const Position& pos, ExtMove* moveList) {
 
-  Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
-  Square ksq = pos.square<KING>(pos.side_to_move());
+  Color us = pos.side_to_move();
+  Bitboard pinned = pos.blockers_for_king(us) & pos.pieces(us);
+  Square ksq = pos.square<KING>(us);
   ExtMove* cur = moveList;
 
   moveList = pos.checkers() ? generate<EVASIONS    >(pos, moveList)

src/movegen.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -21,6 +21,8 @@
 #ifndef MOVEGEN_H_INCLUDED
 #define MOVEGEN_H_INCLUDED
 
+#include <algorithm>
+
 #include "types.h"
 
 class Position;
@@ -36,10 +38,14 @@ enum GenType {
 
 struct ExtMove {
   Move move;
-  Value value;
+  int value;
 
   operator Move() const { return move; }
   void operator=(Move m) { move = m; }
+
+  // Inhibit unwanted implicit conversions to Move
+  // with an ambiguity that yields to a compile error.
+  operator float() const = delete;
 };
 
 inline bool operator<(const ExtMove& f, const ExtMove& s) {
@@ -59,8 +65,7 @@ struct MoveList {
   const ExtMove* end() const { return last; }
   size_t size() const { return last - moveList; }
   bool contains(Move move) const {
-    for (const auto& m : *this) if (m == move) return true;
-    return false;
+    return std::find(begin(), end(), move) != end();
   }
 
 private:

src/movepick.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -21,40 +21,32 @@
 #include <cassert>
 
 #include "movepick.h"
-#include "thread.h"
 
 namespace {
 
   enum Stages {
-    MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES,
-    EVASION, EVASIONS_INIT, ALL_EVASIONS,
-    PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES,
-    QSEARCH_WITH_CHECKS, QCAPTURES_1_INIT, QCAPTURES_1, QCHECKS,
-    QSEARCH_NO_CHECKS, QCAPTURES_2_INIT, QCAPTURES_2,
-    QSEARCH_RECAPTURES, QRECAPTURES
+    MAIN_TT, CAPTURE_INIT, GOOD_CAPTURE, REFUTATION, QUIET_INIT, QUIET, BAD_CAPTURE,
+    EVASION_TT, EVASION_INIT, EVASION,
+    PROBCUT_TT, PROBCUT_INIT, PROBCUT,
+    QSEARCH_TT, QCAPTURE_INIT, QCAPTURE, QCHECK_INIT, QCHECK
   };
 
-  // Our insertion sort, which is guaranteed to be stable, as it should be
-  void insertion_sort(ExtMove* begin, ExtMove* end)
-  {
-    ExtMove tmp, *p, *q;
+  // Helper filter used with select()
+  const auto Any = [](){ return true; };
 
-    for (p = begin + 1; p < end; ++p)
-    {
-        tmp = *p;
-        for (q = p; q != begin && *(q-1) < tmp; --q)
-            *q = *(q-1);
-        *q = tmp;
-    }
-  }
+  // partial_insertion_sort() sorts moves in descending order up to and including
+  // a given limit. The order of moves smaller than the limit is left unspecified.
+  void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) {
 
-  // pick_best() finds the best move in the range (begin, end) and moves it to
-  // the front. It's faster than sorting all the moves in advance when there
-  // are few moves, e.g., the possible captures.
-  Move pick_best(ExtMove* begin, ExtMove* end)
-  {
-      std::swap(*begin, *std::max_element(begin, end));
-      return *begin;
+    for (ExtMove *sortedEnd = begin, *p = begin + 1; p < end; ++p)
+        if (p->value >= limit)
+        {
+            ExtMove tmp = *p, *q;
+            *p = *++sortedEnd;
+            for (q = sortedEnd; q != begin && *(q - 1) < tmp; --q)
+                *q = *(q - 1);
+            *q = tmp;
+        }
   }
 
 } // namespace
@@ -66,285 +58,212 @@ namespace {
 /// search captures, promotions, and some checks) and how important good move
 /// ordering is at the current node.
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Search::Stack* s)
-           : pos(p), ss(s), depth(d) {
+/// MovePicker constructor for the main search
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
+                       const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers)
+           : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch),
+             refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) {
 
   assert(d > DEPTH_ZERO);
 
-  Square prevSq = to_sq((ss-1)->currentMove);
-  countermove = pos.this_thread()->counterMoves[pos.piece_on(prevSq)][prevSq];
-
-  stage = pos.checkers() ? EVASION : MAIN_SEARCH;
+  stage = pos.checkers() ? EVASION_TT : MAIN_TT;
   ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
   stage += (ttMove == MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Square s)
-           : pos(p) {
+/// MovePicker constructor for quiescence search
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
+                       const CapturePieceToHistory* cph, const PieceToHistory** ch, Square rs)
+           : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), recaptureSquare(rs), depth(d) {
 
   assert(d <= DEPTH_ZERO);
 
-  if (pos.checkers())
-      stage = EVASION;
-
-  else if (d > DEPTH_QS_NO_CHECKS)
-      stage = QSEARCH_WITH_CHECKS;
-
-  else if (d > DEPTH_QS_RECAPTURES)
-      stage = QSEARCH_NO_CHECKS;
-
-  else
-  {
-      stage = QSEARCH_RECAPTURES;
-      recaptureSquare = s;
-      return;
-  }
-
-  ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
+  stage = pos.checkers() ? EVASION_TT : QSEARCH_TT;
+  ttMove =    ttm
+           && pos.pseudo_legal(ttm)
+           && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare) ? ttm : MOVE_NONE;
   stage += (ttMove == MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, Value th)
-           : pos(p), threshold(th) {
+/// MovePicker constructor for ProbCut: we generate captures with SEE greater
+/// than or equal to the given threshold.
+MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePieceToHistory* cph)
+           : pos(p), captureHistory(cph), threshold(th) {
 
   assert(!pos.checkers());
 
-  stage = PROBCUT;
-
-  // In ProbCut we generate captures with SEE higher than the given threshold
+  stage = PROBCUT_TT;
   ttMove =   ttm
           && pos.pseudo_legal(ttm)
           && pos.capture(ttm)
-          && pos.see_ge(ttm, threshold + 1)? ttm : MOVE_NONE;
-
+          && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE;
   stage += (ttMove == MOVE_NONE);
 }
 
+/// MovePicker::score() assigns a numerical value to each move in a list, used
+/// for sorting. Captures are ordered by Most Valuable Victim (MVV), preferring
+/// captures with a good history. Quiets moves are ordered using the histories.
+template<GenType Type>
+void MovePicker::score() {
 
-/// score() assigns a numerical value to each move in a move list. The moves with
-/// highest values will be picked first.
-template<>
-void MovePicker::score<CAPTURES>() {
-  // Winning and equal captures in the main search are ordered by MVV, preferring
-  // captures near our home rank. Surprisingly, this appears to perform slightly
-  // better than SEE-based move ordering: exchanging big pieces before capturing
-  // a hanging piece probably helps to reduce the subtree size.
-  // In the main search we want to push captures with negative SEE values to the
-  // badCaptures[] array, but instead of doing it now we delay until the move
-  // has been picked up, saving some SEE calls in case we get a cutoff.
-  for (auto& m : *this)
-      m.value =  PieceValue[MG][pos.piece_on(to_sq(m))]
-               - Value(200 * relative_rank(pos.side_to_move(), to_sq(m)));
-}
-
-template<>
-void MovePicker::score<QUIETS>() {
-
-  const HistoryStats& history = pos.this_thread()->history;
-  const FromToStats& fromTo = pos.this_thread()->fromTo;
-
-  const CounterMoveStats* cm = (ss-1)->counterMoves;
-  const CounterMoveStats* fm = (ss-2)->counterMoves;
-  const CounterMoveStats* f2 = (ss-4)->counterMoves;
-
-  Color c = pos.side_to_move();
+  static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type");
 
   for (auto& m : *this)
-      m.value =      history[pos.moved_piece(m)][to_sq(m)]
-               + (cm ? (*cm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
-               + (fm ? (*fm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
-               + (f2 ? (*f2)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
-               + fromTo.get(c, m);
-}
-
-template<>
-void MovePicker::score<EVASIONS>() {
-  // Try captures ordered by MVV/LVA, then non-captures ordered by history value
-  const HistoryStats& history = pos.this_thread()->history;
-  const FromToStats& fromTo = pos.this_thread()->fromTo;
-  Color c = pos.side_to_move();
-
-  for (auto& m : *this)
-      if (pos.capture(m))
+      if (Type == CAPTURES)
           m.value =  PieceValue[MG][pos.piece_on(to_sq(m))]
-                   - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
-      else
-          m.value = history[pos.moved_piece(m)][to_sq(m)] + fromTo.get(c, m);
+                   + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))] / 8;
+
+      else if (Type == QUIETS)
+          m.value =  (*mainHistory)[pos.side_to_move()][from_to(m)]
+                   + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
+                   + (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]
+                   + (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)];
+
+      else // Type == EVASIONS
+      {
+          if (pos.capture(m))
+              m.value =  PieceValue[MG][pos.piece_on(to_sq(m))]
+                       - Value(type_of(pos.moved_piece(m)));
+          else
+              m.value =  (*mainHistory)[pos.side_to_move()][from_to(m)]
+                       + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
+                       - (1 << 28);
+      }
 }
 
+/// MovePicker::select() returns the next move satisfying a predicate function.
+/// It never returns the TT move.
+template<MovePicker::PickType T, typename Pred>
+Move MovePicker::select(Pred filter) {
 
-/// next_move() is the most important method of the MovePicker class. It returns
-/// a new pseudo legal move every time it is called, until there are no more moves
-/// left. It picks the move with the biggest value from a list of generated moves
-/// taking care not to return the ttMove if it has already been searched.
+  while (cur < endMoves)
+  {
+      if (T == Best)
+          std::swap(*cur, *std::max_element(cur, endMoves));
 
-Move MovePicker::next_move() {
+      move = *cur++;
 
-  Move move;
+      if (move != ttMove && filter())
+          return move;
+  }
+  return move = MOVE_NONE;
+}
 
+/// MovePicker::next_move() is the most important method of the MovePicker class. It
+/// returns a new pseudo legal move every time it is called until there are no more
+/// moves left, picking the move with the highest score from a list of generated moves.
+Move MovePicker::next_move(bool skipQuiets) {
+
+top:
   switch (stage) {
 
-  case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS:
-  case QSEARCH_NO_CHECKS: case PROBCUT:
+  case MAIN_TT:
+  case EVASION_TT:
+  case QSEARCH_TT:
+  case PROBCUT_TT:
       ++stage;
       return ttMove;
 
-  case CAPTURES_INIT:
-      endBadCaptures = cur = moves;
+  case CAPTURE_INIT:
+  case PROBCUT_INIT:
+  case QCAPTURE_INIT:
+      cur = endBadCaptures = moves;
       endMoves = generate<CAPTURES>(pos, cur);
+
       score<CAPTURES>();
       ++stage;
+      goto top;
 
-  case GOOD_CAPTURES:
-      while (cur < endMoves)
-      {
-          move = pick_best(cur++, endMoves);
-          if (move != ttMove)
-          {
-              if (pos.see_ge(move, VALUE_ZERO))
-                  return move;
-
-              // Losing capture, move it to the beginning of the array
-              *endBadCaptures++ = move;
-          }
-      }
-
-      ++stage;
-      move = ss->killers[0];  // First killer move
-      if (    move != MOVE_NONE
-          &&  move != ttMove
-          &&  pos.pseudo_legal(move)
-          && !pos.capture(move))
+  case GOOD_CAPTURE:
+      if (select<Best>([&](){
+                       return pos.see_ge(move, Value(-55 * (cur-1)->value / 1024)) ?
+                              // Move losing capture to endBadCaptures to be tried later
+                              true : (*endBadCaptures++ = move, false); }))
           return move;
 
-  case KILLERS:
-      ++stage;
-      move = ss->killers[1]; // Second killer move
-      if (    move != MOVE_NONE
-          &&  move != ttMove
-          &&  pos.pseudo_legal(move)
-          && !pos.capture(move))
-          return move;
+      // Prepare the pointers to loop over the refutations array
+      cur = std::begin(refutations);
+      endMoves = std::end(refutations);
+
+      // If the countermove is the same as a killer, skip it
+      if (   refutations[0].move == refutations[2].move
+          || refutations[1].move == refutations[2].move)
+          --endMoves;
 
-  case COUNTERMOVE:
       ++stage;
-      move = countermove;
-      if (    move != MOVE_NONE
-          &&  move != ttMove
-          &&  move != ss->killers[0]
-          &&  move != ss->killers[1]
-          &&  pos.pseudo_legal(move)
-          && !pos.capture(move))
+      /* fallthrough */
+
+  case REFUTATION:
+      if (select<Next>([&](){ return    move != MOVE_NONE
+                                    && !pos.capture(move)
+                                    &&  pos.pseudo_legal(move); }))
           return move;
+      ++stage;
+      /* fallthrough */
 
   case QUIET_INIT:
       cur = endBadCaptures;
       endMoves = generate<QUIETS>(pos, cur);
+
       score<QUIETS>();
-      if (depth < 3 * ONE_PLY)
-      {
-          ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m)
-                                             { return m.value > VALUE_ZERO; });
-          insertion_sort(cur, goodQuiet);
-      } else
-          insertion_sort(cur, endMoves);
+      partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY);
       ++stage;
+      /* fallthrough */
 
   case QUIET:
-      while (cur < endMoves)
-      {
-          move = *cur++;
-          if (   move != ttMove
-              && move != ss->killers[0]
-              && move != ss->killers[1]
-              && move != countermove)
-              return move;
-      }
+      if (   !skipQuiets
+          && select<Next>([&](){return   move != refutations[0]
+                                      && move != refutations[1]
+                                      && move != refutations[2];}))
+          return move;
+
+      // Prepare the pointers to loop over the bad captures
+      cur = moves;
+      endMoves = endBadCaptures;
+
       ++stage;
-      cur = moves; // Point to beginning of bad captures
+      /* fallthrough */
 
-  case BAD_CAPTURES:
-      if (cur < endBadCaptures)
-          return *cur++;
-      break;
+  case BAD_CAPTURE:
+      return select<Next>(Any);
 
-  case EVASIONS_INIT:
+  case EVASION_INIT:
       cur = moves;
       endMoves = generate<EVASIONS>(pos, cur);
+
       score<EVASIONS>();
       ++stage;
+      /* fallthrough */
 
-  case ALL_EVASIONS:
-      while (cur < endMoves)
-      {
-          move = pick_best(cur++, endMoves);
-          if (move != ttMove)
-              return move;
-      }
-      break;
+  case EVASION:
+      return select<Best>(Any);
+
+  case PROBCUT:
+      return select<Best>([&](){ return pos.see_ge(move, threshold); });
+
+  case QCAPTURE:
+      if (select<Best>([&](){ return   depth > DEPTH_QS_RECAPTURES
+                                    || to_sq(move) == recaptureSquare; }))
+          return move;
+
+      // If we did not find any move and we do not try checks, we have finished
+      if (depth != DEPTH_QS_CHECKS)
+          return MOVE_NONE;
 
-  case PROBCUT_INIT:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
       ++stage;
+      /* fallthrough */
 
-  case PROBCUT_CAPTURES:
-      while (cur < endMoves)
-      {
-          move = pick_best(cur++, endMoves);
-          if (   move != ttMove
-              && pos.see_ge(move, threshold + 1))
-              return move;
-      }
-      break;
-
-  case QCAPTURES_1_INIT: case QCAPTURES_2_INIT:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
-      ++stage;
-
-  case QCAPTURES_1: case QCAPTURES_2:
-      while (cur < endMoves)
-      {
-          move = pick_best(cur++, endMoves);
-          if (move != ttMove)
-              return move;
-      }
-      if (stage == QCAPTURES_2)
-          break;
+  case QCHECK_INIT:
       cur = moves;
       endMoves = generate<QUIET_CHECKS>(pos, cur);
+
       ++stage;
+      /* fallthrough */
 
-  case QCHECKS:
-      while (cur < endMoves)
-      {
-          move = cur++->move;
-          if (move != ttMove)
-              return move;
-      }
-      break;
-
-  case QSEARCH_RECAPTURES:
-      cur = moves;
-      endMoves = generate<CAPTURES>(pos, cur);
-      score<CAPTURES>();
-      ++stage;
-
-  case QRECAPTURES:
-      while (cur < endMoves)
-      {
-          move = pick_best(cur++, endMoves);
-          if (to_sq(move) == recaptureSquare)
-              return move;
-      }
-      break;
-
-  default:
-      assert(false);
+  case QCHECK:
+      return select<Next>(Any);
   }
 
-  return MOVE_NONE;
+  assert(false);
+  return MOVE_NONE; // Silence warning
 }

src/movepick.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -21,68 +21,88 @@
 #ifndef MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 
-#include <algorithm> // For std::max
-#include <cstring>   // For std::memset
+#include <array>
+#include <limits>
+#include <type_traits>
 
 #include "movegen.h"
 #include "position.h"
 #include "types.h"
 
+/// StatsEntry stores the stat table value. It is usually a number but could
+/// be a move or even a nested history. We use a class instead of naked value
+/// to directly call history update operator<<() on the entry so to use stats
+/// tables at caller sites as simple multi-dim arrays.
+template<typename T, int D>
+class StatsEntry {
 
-/// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store History and Countermoves. History records how often
-/// different moves have been successful or unsuccessful during the current search
-/// and is used for reduction and move ordering decisions.
-/// Countermoves store the move that refute a previous one. Entries are stored
-/// using only the moving piece and destination square, hence two moves with
-/// different origin but same destination and piece will be considered identical.
-template<typename T, bool CM = false>
-struct Stats {
+  T entry;
 
-  static const Value Max = Value(1 << 28);
+public:
+  void operator=(const T& v) { entry = v; }
+  T* operator&() { return &entry; }
+  T* operator->() { return &entry; }
+  operator const T&() const { return entry; }
 
-  const T* operator[](Piece pc) const { return table[pc]; }
-  T* operator[](Piece pc) { return table[pc]; }
-  void clear() { std::memset(table, 0, sizeof(table)); }
-  void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
-  void update(Piece pc, Square to, Value v) {
+  void operator<<(int bonus) {
+    assert(abs(bonus) <= D); // Ensure range is [-D, D]
+    static_assert(D <= std::numeric_limits<T>::max(), "D overflows T");
 
-    if (abs(int(v)) >= 324)
-        return;
+    entry += bonus - entry * abs(bonus) / D;
 
-    table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
-    table[pc][to] += int(v) * 32;
+    assert(abs(entry) <= D);
   }
-
-private:
-  T table[PIECE_NB][SQUARE_NB];
 };
 
-typedef Stats<Move> MoveStats;
-typedef Stats<Value, false> HistoryStats;
-typedef Stats<Value,  true> CounterMoveStats;
-typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
+/// Stats is a generic N-dimensional array used to store various statistics.
+/// The first template parameter T is the base type of the array, the second
+/// template parameter D limits the range of updates in [-D, D] when we update
+/// values with the << operator, while the last parameters (Size and Sizes)
+/// encode the dimensions of the array.
+template <typename T, int D, int Size, int... Sizes>
+struct Stats : public std::array<Stats<T, D, Sizes...>, Size>
+{
+  typedef Stats<T, D, Size, Sizes...> stats;
 
-struct FromToStats {
+  void fill(const T& v) {
 
-  Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
-  void clear() { std::memset(table, 0, sizeof(table)); }
-  void update(Color c, Move m, Value v) {
+    // For standard-layout 'this' points to first struct member
+    assert(std::is_standard_layout<stats>::value);
 
-    if (abs(int(v)) >= 324)
-        return;
-
-    Square from = from_sq(m);
-    Square to = to_sq(m);
-
-    table[c][from][to] -= table[c][from][to] * abs(int(v)) / 324;
-    table[c][from][to] += int(v) * 32;
+    typedef StatsEntry<T, D> entry;
+    entry* p = reinterpret_cast<entry*>(this);
+    std::fill(p, p + sizeof(*this) / sizeof(entry), v);
   }
-
-private:
-  Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
 };
 
+template <typename T, int D, int Size>
+struct Stats<T, D, Size> : public std::array<StatsEntry<T, D>, Size> {};
+
+/// In stats table, D=0 means that the template parameter is not used
+enum StatsParams { NOT_USED = 0 };
+
+
+/// ButterflyHistory records how often quiet moves have been successful or
+/// unsuccessful during the current search, and is used for reduction and move
+/// ordering decisions. It uses 2 tables (one for each color) indexed by
+/// the move's from and to squares, see chessprogramming.wikispaces.com/Butterfly+Boards
+typedef Stats<int16_t, 10692, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
+
+/// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous
+/// move, see chessprogramming.wikispaces.com/Countermove+Heuristic
+typedef Stats<Move, NOT_USED, PIECE_NB, SQUARE_NB> CounterMoveHistory;
+
+/// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type]
+typedef Stats<int16_t, 10692, PIECE_NB, SQUARE_NB, PIECE_TYPE_NB> CapturePieceToHistory;
+
+/// PieceToHistory is like ButterflyHistory but is addressed by a move's [piece][to]
+typedef Stats<int16_t, 29952, PIECE_NB, SQUARE_NB> PieceToHistory;
+
+/// ContinuationHistory is the combined history of a given pair of moves, usually
+/// the current one given a previous one. The nested history table is based on
+/// PieceToHistory instead of ButterflyBoards.
+typedef Stats<PieceToHistory, NOT_USED, PIECE_NB, SQUARE_NB> ContinuationHistory;
+
 
 /// MovePicker class is used to pick one pseudo legal move at a time from the
 /// current position. The most important method is next_move(), which returns a
@@ -90,33 +110,42 @@ private:
 /// when MOVE_NONE is returned. In order to improve the efficiency of the alpha
 /// beta algorithm, MovePicker attempts to return the moves which are most likely
 /// to get a cut-off first.
-namespace Search { struct Stack; }
-
 class MovePicker {
+
+  enum PickType { Next, Best };
+
 public:
   MovePicker(const MovePicker&) = delete;
   MovePicker& operator=(const MovePicker&) = delete;
-
-  MovePicker(const Position&, Move, Value);
-  MovePicker(const Position&, Move, Depth, Square);
-  MovePicker(const Position&, Move, Depth, Search::Stack*);
-
-  Move next_move();
+  MovePicker(const Position&, Move, Value, const CapturePieceToHistory*);
+  MovePicker(const Position&, Move, Depth, const ButterflyHistory*,
+                                           const CapturePieceToHistory*,
+                                           const PieceToHistory**,
+                                           Square);
+  MovePicker(const Position&, Move, Depth, const ButterflyHistory*,
+                                           const CapturePieceToHistory*,
+                                           const PieceToHistory**,
+                                           Move,
+                                           Move*);
+  Move next_move(bool skipQuiets = false);
 
 private:
+  template<PickType T, typename Pred> Move select(Pred);
   template<GenType> void score();
   ExtMove* begin() { return cur; }
   ExtMove* end() { return endMoves; }
 
   const Position& pos;
-  const Search::Stack* ss;
-  Move countermove;
-  Depth depth;
+  const ButterflyHistory* mainHistory;
+  const CapturePieceToHistory* captureHistory;
+  const PieceToHistory** continuationHistory;
   Move ttMove;
+  ExtMove refutations[3], *cur, *endMoves, *endBadCaptures;
+  int stage;
+  Move move;
   Square recaptureSquare;
   Value threshold;
-  int stage;
-  ExtMove *cur, *endMoves, *endBadCaptures;
+  Depth depth;
   ExtMove moves[MAX_MOVES];
 };
 

src/pawns.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,84 +31,56 @@ namespace {
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
 
-  // Isolated pawn penalty by opposed flag
-  const Score Isolated[2] = { S(45, 40), S(30, 27) };
+  // Pawn penalties
+  constexpr Score Backward = S( 9, 24);
+  constexpr Score Doubled  = S(11, 56);
+  constexpr Score Isolated = S( 5, 15);
 
-  // Backward pawn penalty by opposed flag
-  const Score Backward[2] = { S(56, 33), S(41, 19) };
+  // Connected pawn bonus by opposed, phalanx, #support and rank
+  Score Connected[2][2][3][RANK_NB];
 
-  // Unsupported pawn penalty for pawns which are neither isolated or backward
-  const Score Unsupported = S(17, 8);
-
-  // Connected pawn bonus by opposed, phalanx, twice supported and rank
-  Score Connected[2][2][2][RANK_NB];
-
-  // Doubled pawn penalty
-  const Score Doubled = S(18,38);
-
-  // Lever bonus by rank
-  const Score Lever[RANK_NB] = {
-    S( 0,  0), S( 0,  0), S(0, 0), S(0, 0),
-    S(17, 16), S(33, 32), S(0, 0), S(0, 0)
+  // Strength of pawn shelter for our king by [distance from edge][rank].
+  // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
+  constexpr Value ShelterStrength[int(FILE_NB) / 2][RANK_NB] = {
+    { V( -6), V( 81), V( 93), V( 58), V( 39), V( 18), V(  25) },
+    { V(-43), V( 61), V( 35), V(-49), V(-29), V(-11), V( -63) },
+    { V(-10), V( 75), V( 23), V( -2), V( 32), V(  3), V( -45) },
+    { V(-39), V(-13), V(-29), V(-52), V(-48), V(-67), V(-166) }
   };
 
-  // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
-  const Value ShelterWeakness[][RANK_NB] = {
-    { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
-    { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) },
-    { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) },
-    { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) }
+  // Danger of enemy pawns moving toward our king by [distance from edge][rank].
+  // RANK_1 = 0 is used for files where the enemy has no pawn, or their pawn
+  // is behind our king.
+  constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = {
+    { V( 89), V(107), V(123), V(93), V(57), V( 45), V( 51) },
+    { V( 44), V(-18), V(123), V(46), V(39), V( -7), V( 23) },
+    { V(  4), V( 52), V(162), V(37), V( 7), V(-14), V( -2) },
+    { V(-10), V(-14), V( 90), V(15), V( 2), V( -7), V(-16) }
   };
 
-  // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
-  const Value StormDanger[][4][RANK_NB] = {
-    { { V( 0),  V(  67), V( 134), V(38), V(32) },
-      { V( 0),  V(  57), V( 139), V(37), V(22) },
-      { V( 0),  V(  43), V( 115), V(43), V(27) },
-      { V( 0),  V(  68), V( 124), V(57), V(32) } },
-    { { V(20),  V(  43), V( 100), V(56), V(20) },
-      { V(23),  V(  20), V(  98), V(40), V(15) },
-      { V(23),  V(  39), V( 103), V(36), V(18) },
-      { V(28),  V(  19), V( 108), V(42), V(26) } },
-    { { V( 0),  V(   0), V(  75), V(14), V( 2) },
-      { V( 0),  V(   0), V( 150), V(30), V( 4) },
-      { V( 0),  V(   0), V( 160), V(22), V( 5) },
-      { V( 0),  V(   0), V( 166), V(24), V(13) } },
-    { { V( 0),  V(-283), V(-281), V(57), V(31) },
-      { V( 0),  V(  58), V( 141), V(39), V(18) },
-      { V( 0),  V(  65), V( 142), V(48), V(32) },
-      { V( 0),  V(  60), V( 126), V(51), V(19) } }
-  };
-
-  // Max bonus for king safety. Corresponds to start position with all the pawns
-  // in front of the king and no enemy pawn on the horizon.
-  const Value MaxSafetyBonus = V(258);
-
   #undef S
   #undef V
 
   template<Color Us>
   Score evaluate(const Position& pos, Pawns::Entry* e) {
 
-    const Color  Them  = (Us == WHITE ? BLACK      : WHITE);
-    const Square Up    = (Us == WHITE ? NORTH      : SOUTH);
-    const Square Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Square Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+    constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
+    constexpr Direction Up   = (Us == WHITE ? NORTH : SOUTH);
 
     Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
+    Bitboard lever, leverPush;
     Square s;
-    bool opposed, lever, connected, backward;
+    bool opposed, backward;
     Score score = SCORE_ZERO;
     const Square* pl = pos.squares<PAWN>(Us);
-    const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
 
-    Bitboard ourPawns   = pos.pieces(Us  , PAWN);
+    Bitboard ourPawns   = pos.pieces(  Us, PAWN);
     Bitboard theirPawns = pos.pieces(Them, PAWN);
 
-    e->passedPawns[Us]   = e->pawnAttacksSpan[Us] = 0;
+    e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
     e->semiopenFiles[Us] = 0xFF;
     e->kingSquares[Us]   = SQ_NONE;
-    e->pawnAttacks[Us]   = shift<Right>(ourPawns) | shift<Left>(ourPawns);
+    e->pawnAttacks[Us]   = pawn_attacks_bb<Us>(ourPawns);
     e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
     e->pawnsOnSquares[Us][WHITE] = pos.count<PAWN>(Us) - e->pawnsOnSquares[Us][BLACK];
 
@@ -123,55 +95,50 @@ namespace {
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
 
         // Flag the pawn
-        opposed    = theirPawns & forward_bb(Us, s);
+        opposed    = theirPawns & forward_file_bb(Us, s);
         stoppers   = theirPawns & passed_pawn_mask(Us, s);
-        lever      = theirPawns & pawnAttacksBB[s];
-        doubled    = ourPawns   & (s + Up);
+        lever      = theirPawns & PawnAttacks[Us][s];
+        leverPush  = theirPawns & PawnAttacks[Us][s + Up];
+        doubled    = ourPawns   & (s - Up);
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
         supported  = neighbours & rank_bb(s - Up);
-        connected  = supported | phalanx;
 
-        // A pawn is backward when it is behind all pawns of the same color on the
-        // adjacent files and cannot be safely advanced.
-        if (!neighbours || lever || relative_rank(Us, s) >= RANK_5)
-            backward = false;
-        else
-        {
-            // Find the backmost rank with neighbours or stoppers
-            b = rank_bb(backmost_sq(Us, neighbours | stoppers));
-
-            // The pawn is backward when it cannot safely progress to that rank:
-            // either there is a stopper in the way on this rank, or there is a
-            // stopper on adjacent file which controls the way to that rank.
-            backward = (b | shift<Up>(b & adjacent_files_bb(f))) & stoppers;
-
-            assert(!backward || !(pawn_attack_span(Them, s + Up) & neighbours));
-        }
+        // A pawn is backward when it is behind all pawns of the same color
+        // on the adjacent files and cannot be safely advanced.
+        backward =  !(ourPawns & pawn_attack_span(Them, s + Up))
+                  && (stoppers & (leverPush | (s + Up)));
 
         // Passed pawns will be properly scored in evaluation because we need
-        // full attack info to evaluate them.
-        if (!stoppers && !(ourPawns & forward_bb(Us, s)))
+        // full attack info to evaluate them. Include also not passed pawns
+        // which could become passed after one or two pawn pushes when are
+        // not attacked more times than defended.
+        if (   !(stoppers ^ lever ^ leverPush)
+            && popcount(supported) >= popcount(lever) - 1
+            && popcount(phalanx)   >= popcount(leverPush))
             e->passedPawns[Us] |= s;
 
+        else if (   stoppers == SquareBB[s + Up]
+                 && relative_rank(Us, s) >= RANK_5)
+        {
+            b = shift<Up>(supported) & ~theirPawns;
+            while (b)
+                if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)]))
+                    e->passedPawns[Us] |= s;
+        }
+
         // Score this pawn
-        if (!neighbours)
-            score -= Isolated[opposed];
+        if (supported | phalanx)
+            score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
+
+        else if (!neighbours)
+            score -= Isolated, e->weakUnopposed[Us] += !opposed;
 
         else if (backward)
-            score -= Backward[opposed];
+            score -= Backward, e->weakUnopposed[Us] += !opposed;
 
-        else if (!supported)
-            score -= Unsupported;
-
-        if (connected)
-            score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
-
-        if (doubled)
+        if (doubled && !supported)
             score -= Doubled;
-
-        if (lever)
-            score += Lever[relative_rank(Us, s)];
     }
 
     return score;
@@ -187,16 +154,17 @@ namespace Pawns {
 
 void init() {
 
-  static const int Seed[RANK_NB] = { 0, 8, 19, 13, 71, 94, 169, 324 };
+  static constexpr int Seed[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 };
 
   for (int opposed = 0; opposed <= 1; ++opposed)
       for (int phalanx = 0; phalanx <= 1; ++phalanx)
-          for (int apex = 0; apex <= 1; ++apex)
+          for (int support = 0; support <= 2; ++support)
               for (Rank r = RANK_2; r < RANK_8; ++r)
   {
-      int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
-      v += (apex ? v / 2 : 0);
-      Connected[opposed][phalanx][apex][r] = make_score(v, v * 5 / 8);
+      int v = 17 * support;
+      v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
+
+      Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
   }
 }
 
@@ -215,43 +183,46 @@ Entry* probe(const Position& pos) {
       return e;
 
   e->key = key;
-  e->score = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
-  e->asymmetry = popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
+  e->scores[WHITE] = evaluate<WHITE>(pos, e);
+  e->scores[BLACK] = evaluate<BLACK>(pos, e);
   e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
+  e->asymmetry = popcount(  (e->passedPawns[WHITE]   | e->passedPawns[BLACK])
+                          | (e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]));
+
   return e;
 }
 
 
-/// Entry::shelter_storm() calculates shelter and storm penalties for the file
-/// the king is on, as well as the two adjacent files.
+/// Entry::evaluate_shelter() calculates the shelter bonus and the storm
+/// penalty for a king, looking at the king file and the two closest files.
 
 template<Color Us>
-Value Entry::shelter_storm(const Position& pos, Square ksq) {
+Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
 
-  const Color Them = (Us == WHITE ? BLACK : WHITE);
+  constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
+  constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+  constexpr Bitboard  BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
 
-  enum { NoFriendlyPawn, Unblocked, BlockedByPawn, BlockedByKing };
-
-  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq));
+  Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
   Bitboard ourPawns = b & pos.pieces(Us);
   Bitboard theirPawns = b & pos.pieces(Them);
-  Value safety = MaxSafetyBonus;
-  File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
 
-  for (File f = center - File(1); f <= center + File(1); ++f)
+  Value safety = (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq) ?
+                 Value(374) : Value(5);
+
+  File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
+  for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);
-      Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+      int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
 
-      b  = theirPawns & file_bb(f);
-      Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      b = theirPawns & file_bb(f);
+      int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
 
-      safety -=  ShelterWeakness[std::min(f, FILE_H - f)][rkUs]
-               + StormDanger
-                 [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing  :
-                  rkUs   == RANK_1                                          ? NoFriendlyPawn :
-                  rkThem == rkUs + 1                                        ? BlockedByPawn  : Unblocked]
-                 [std::min(f, FILE_H - f)][rkThem];
+      int d = std::min(f, ~f);
+      safety += ShelterStrength[d][ourRank];
+      safety -= (ourRank && (ourRank == theirRank - 1)) ? 66 * (theirRank == RANK_3)
+                                                        : UnblockedStorm[d][theirRank];
   }
 
   return safety;
@@ -262,30 +233,31 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
 /// when king square changes, which is about 20% of total king_safety() calls.
 
 template<Color Us>
-Score Entry::do_king_safety(const Position& pos, Square ksq) {
+Score Entry::do_king_safety(const Position& pos) {
 
+  Square ksq = pos.square<KING>(Us);
   kingSquares[Us] = ksq;
   castlingRights[Us] = pos.can_castle(Us);
   int minKingPawnDistance = 0;
 
   Bitboard pawns = pos.pieces(Us, PAWN);
   if (pawns)
-      while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
+      while (!(DistanceRingBB[ksq][++minKingPawnDistance] & pawns)) {}
 
-  Value bonus = shelter_storm<Us>(pos, ksq);
+  Value bonus = evaluate_shelter<Us>(pos, ksq);
 
   // If we can castle use the bonus after the castling if it is bigger
-  if (pos.can_castle(MakeCastling<Us, KING_SIDE>::right))
-      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
+  if (pos.can_castle(Us | KING_SIDE))
+      bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1)));
 
-  if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
-      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
+  if (pos.can_castle(Us | QUEEN_SIDE))
+      bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1)));
 
   return make_score(bonus, -16 * minKingPawnDistance);
 }
 
 // Explicit template instantiation
-template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
-template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<WHITE>(const Position& pos);
+template Score Entry::do_king_safety<BLACK>(const Position& pos);
 
 } // namespace Pawns

src/pawns.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -33,10 +33,11 @@ namespace Pawns {
 
 struct Entry {
 
-  Score pawns_score() const { return score; }
+  Score pawn_score(Color c) const { return scores[c]; }
   Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
   Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
   Bitboard pawn_attacks_span(Color c) const { return pawnAttacksSpan[c]; }
+  int weak_unopposed(Color c) const { return weakUnopposed[c]; }
   int pawn_asymmetry() const { return asymmetry; }
   int open_files() const { return openFiles; }
 
@@ -44,33 +45,30 @@ struct Entry {
     return semiopenFiles[c] & (1 << f);
   }
 
-  int semiopen_side(Color c, File f, bool leftSide) const {
-    return semiopenFiles[c] & (leftSide ? (1 << f) - 1 : ~((1 << (f + 1)) - 1));
-  }
-
   int pawns_on_same_color_squares(Color c, Square s) const {
-    return pawnsOnSquares[c][!!(DarkSquares & s)];
+    return pawnsOnSquares[c][bool(DarkSquares & s)];
   }
 
   template<Color Us>
-  Score king_safety(const Position& pos, Square ksq) {
-    return  kingSquares[Us] == ksq && castlingRights[Us] == pos.can_castle(Us)
-          ? kingSafety[Us] : (kingSafety[Us] = do_king_safety<Us>(pos, ksq));
+  Score king_safety(const Position& pos) {
+    return  kingSquares[Us] == pos.square<KING>(Us) && castlingRights[Us] == pos.can_castle(Us)
+          ? kingSafety[Us] : (kingSafety[Us] = do_king_safety<Us>(pos));
   }
 
   template<Color Us>
-  Score do_king_safety(const Position& pos, Square ksq);
+  Score do_king_safety(const Position& pos);
 
   template<Color Us>
-  Value shelter_storm(const Position& pos, Square ksq);
+  Value evaluate_shelter(const Position& pos, Square ksq);
 
   Key key;
-  Score score;
+  Score scores[COLOR_NB];
   Bitboard passedPawns[COLOR_NB];
   Bitboard pawnAttacks[COLOR_NB];
   Bitboard pawnAttacksSpan[COLOR_NB];
   Square kingSquares[COLOR_NB];
   Score kingSafety[COLOR_NB];
+  int weakUnopposed[COLOR_NB];
   int castlingRights[COLOR_NB];
   int semiopenFiles[COLOR_NB];
   int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]

src/position.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -32,46 +32,51 @@
 #include "thread.h"
 #include "tt.h"
 #include "uci.h"
+#include "syzygy/tbprobe.h"
 
 using std::string;
 
-namespace PSQT {
-  extern Score psq[PIECE_NB][SQUARE_NB];
-}
-
 namespace Zobrist {
 
   Key psq[PIECE_NB][SQUARE_NB];
   Key enpassant[FILE_NB];
   Key castling[CASTLING_RIGHT_NB];
-  Key side;
+  Key side, noPawns;
 }
 
 namespace {
 
 const string PieceToChar(" PNBRQK  pnbrqk");
 
-// min_attacker() is a helper function used by see() to locate the least
+constexpr Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
+                             B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING };
+
+// min_attacker() is a helper function used by see_ge() to locate the least
 // valuable attacker for the side to move, remove the attacker we just found
 // from the bitboards and scan for new X-ray attacks behind it.
 
 template<int Pt>
-PieceType min_attacker(const Bitboard* bb, Square to, Bitboard stmAttackers,
+PieceType min_attacker(const Bitboard* byTypeBB, Square to, Bitboard stmAttackers,
                        Bitboard& occupied, Bitboard& attackers) {
 
-  Bitboard b = stmAttackers & bb[Pt];
+  Bitboard b = stmAttackers & byTypeBB[Pt];
   if (!b)
-      return min_attacker<Pt+1>(bb, to, stmAttackers, occupied, attackers);
+      return min_attacker<Pt + 1>(byTypeBB, to, stmAttackers, occupied, attackers);
 
-  occupied ^= b & ~(b - 1);
+  occupied ^= lsb(b); // Remove the attacker from occupied
 
+  // Add any X-ray attack behind the just removed piece. For instance with
+  // rooks in a8 and a7 attacking a1, after removing a7 we add rook in a8.
+  // Note that new added attackers can be of any color.
   if (Pt == PAWN || Pt == BISHOP || Pt == QUEEN)
-      attackers |= attacks_bb<BISHOP>(to, occupied) & (bb[BISHOP] | bb[QUEEN]);
+      attackers |= attacks_bb<BISHOP>(to, occupied) & (byTypeBB[BISHOP] | byTypeBB[QUEEN]);
 
   if (Pt == ROOK || Pt == QUEEN)
-      attackers |= attacks_bb<ROOK>(to, occupied) & (bb[ROOK] | bb[QUEEN]);
+      attackers |= attacks_bb<ROOK>(to, occupied) & (byTypeBB[ROOK] | byTypeBB[QUEEN]);
 
-  attackers &= occupied; // After X-ray that may add already processed pieces
+  // X-ray may add already processed pieces because byTypeBB[] is constant: in
+  // the rook example, now attackers contains _again_ rook in a7, so remove it.
+  attackers &= occupied;
   return (PieceType)Pt;
 }
 
@@ -98,15 +103,42 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) {
   }
 
   os << "\nFen: " << pos.fen() << "\nKey: " << std::hex << std::uppercase
-     << std::setfill('0') << std::setw(16) << pos.key() << std::dec << "\nCheckers: ";
+     << std::setfill('0') << std::setw(16) << pos.key()
+     << std::setfill(' ') << std::dec << "\nCheckers: ";
 
   for (Bitboard b = pos.checkers(); b; )
       os << UCI::square(pop_lsb(&b)) << " ";
 
+  if (    int(Tablebases::MaxCardinality) >= popcount(pos.pieces())
+      && !pos.can_castle(ANY_CASTLING))
+  {
+      StateInfo st;
+      Position p;
+      p.set(pos.fen(), pos.is_chess960(), &st, pos.this_thread());
+      Tablebases::ProbeState s1, s2;
+      Tablebases::WDLScore wdl = Tablebases::probe_wdl(p, &s1);
+      int dtz = Tablebases::probe_dtz(p, &s2);
+      os << "\nTablebases WDL: " << std::setw(4) << wdl << " (" << s1 << ")"
+         << "\nTablebases DTZ: " << std::setw(4) << dtz << " (" << s2 << ")";
+  }
+
   return os;
 }
 
 
+// Marcel van Kervinck's cuckoo algorithm for fast detection of "upcoming repetition"
+// situations. Description of the algorithm in the following paper:
+// https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf
+
+// First and second hash functions for indexing the cuckoo tables
+inline int H1(Key h) { return h & 0x1fff; }
+inline int H2(Key h) { return (h >> 16) & 0x1fff; }
+
+// Cuckoo tables with Zobrist hashes of valid reversible moves, and the moves themselves
+Key cuckoo[8192];
+Move cuckooMove[8192];
+
+
 /// Position::init() initializes at startup the various arrays used to compute
 /// hash keys.
 
@@ -133,6 +165,31 @@ void Position::init() {
   }
 
   Zobrist::side = rng.rand<Key>();
+  Zobrist::noPawns = rng.rand<Key>();
+
+  // Prepare the cuckoo tables
+  std::memset(cuckoo, 0, sizeof(cuckoo));
+  std::memset(cuckooMove, 0, sizeof(cuckooMove));
+  int count = 0;
+  for (Piece pc : Pieces)
+      for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
+          for (Square s2 = Square(s1 + 1); s2 <= SQ_H8; ++s2)
+              if (PseudoAttacks[type_of(pc)][s1] & s2)
+              {
+                  Move move = make_move(s1, s2);
+                  Key key = Zobrist::psq[pc][s1] ^ Zobrist::psq[pc][s2] ^ Zobrist::side;
+                  int i = H1(key);
+                  while (true)
+                  {
+                      std::swap(cuckoo[i], key);
+                      std::swap(cuckooMove[i], move);
+                      if (move == 0)   // Arrived at empty slot ?
+                          break;
+                      i = (i == H1(key)) ? H2(key) : H1(key); // Push victim to alternative slot
+                  }
+                  count++;
+             }
+  assert(count == 3668);
 }
 
 
@@ -164,8 +221,9 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
 
    4) En passant target square (in algebraic notation). If there's no en passant
       target square, this is "-". If a pawn has just made a 2-square move, this
-      is the position "behind" the pawn. This is recorded regardless of whether
-      there is a pawn in position to make an en passant capture.
+      is the position "behind" the pawn. This is recorded only if there is a pawn
+      in position to make an en passant capture, and if there really is a pawn
+      that might have advanced two squares.
 
    5) Halfmove clock. This is the number of halfmoves since the last pawn advance
       or capture. This is used to determine if a draw can be claimed under the
@@ -191,10 +249,10 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
   while ((ss >> token) && !isspace(token))
   {
       if (isdigit(token))
-          sq += Square(token - '0'); // Advance the given number of files
+          sq += (token - '0') * EAST; // Advance the given number of files
 
       else if (token == '/')
-          sq -= Square(16);
+          sq += 2 * SOUTH;
 
       else if ((idx = PieceToChar.find(token)) != string::npos)
       {
@@ -242,7 +300,8 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
   {
       st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
 
-      if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN)))
+      if (   !(attackers_to(st->epSquare) & pieces(sideToMove, PAWN))
+          || !(pieces(~sideToMove, PAWN) & (st->epSquare + pawn_push(~sideToMove))))
           st->epSquare = SQ_NONE;
   }
   else
@@ -251,7 +310,7 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th
   // 5-6. Halfmove clock and fullmove number
   ss >> std::skipws >> st->rule50 >> gamePly;
 
-  // Convert from fullmove starting from 1 to ply starting from 0,
+  // Convert from fullmove starting from 1 to gamePly starting from 0,
   // handle also common incorrect FEN with fullmove = 0.
   gamePly = std::max(2 * (gamePly - 1), 0) + (sideToMove == BLACK);
 
@@ -296,8 +355,8 @@ void Position::set_castling_right(Color c, Square rfrom) {
 
 void Position::set_check_info(StateInfo* si) const {
 
-  si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square<KING>(WHITE), si->pinnersForKing[WHITE]);
-  si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square<KING>(BLACK), si->pinnersForKing[BLACK]);
+  si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square<KING>(WHITE), si->pinners[BLACK]);
+  si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square<KING>(BLACK), si->pinners[WHITE]);
 
   Square ksq = square<KING>(~sideToMove);
 
@@ -317,9 +376,9 @@ void Position::set_check_info(StateInfo* si) const {
 
 void Position::set_state(StateInfo* si) const {
 
-  si->key = si->pawnKey = si->materialKey = 0;
+  si->key = si->materialKey = 0;
+  si->pawnKey = Zobrist::noPawns;
   si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO;
-  si->psq = SCORE_ZERO;
   si->checkersBB = attackers_to(square<KING>(sideToMove)) & pieces(~sideToMove);
 
   set_check_info(si);
@@ -329,7 +388,6 @@ void Position::set_state(StateInfo* si) const {
       Square s = pop_lsb(&b);
       Piece pc = piece_on(s);
       si->key ^= Zobrist::psq[pc][s];
-      si->psq += PSQT::psq[pc][s];
   }
 
   if (si->epSquare != SQ_NONE)
@@ -357,6 +415,27 @@ void Position::set_state(StateInfo* si) const {
 }
 
 
+/// Position::set() is an overload to initialize the position object with
+/// the given endgame code string like "KBPKN". It is mainly a helper to
+/// get the material key out of an endgame code.
+
+Position& Position::set(const string& code, Color c, StateInfo* si) {
+
+  assert(code.length() > 0 && code.length() < 8);
+  assert(code[0] == 'K');
+
+  string sides[] = { code.substr(code.find('K', 1)),      // Weak
+                     code.substr(0, code.find('K', 1)) }; // Strong
+
+  std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
+
+  string fenStr = "8/" + sides[0] + char(8 - sides[0].length() + '0') + "/8/8/8/8/"
+                       + sides[1] + char(8 - sides[1].length() + '0') + "/8 w - - 0 10";
+
+  return set(fenStr, false, si, nullptr);
+}
+
+
 /// Position::fen() returns a FEN representation of the position. In case of
 /// Chess960 the Shredder-FEN notation is used. This is mainly a debugging function.
 
@@ -407,19 +486,6 @@ const string Position::fen() const {
 }
 
 
-/// Position::game_phase() calculates the game phase interpolating total non-pawn
-/// material between endgame and midgame limits.
-
-Phase Position::game_phase() const {
-
-  Value npm = st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK];
-
-  npm = std::max(EndgameLimit, std::min(npm, MidgameLimit));
-
-  return Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));
-}
-
-
 /// Position::slider_blockers() returns a bitboard of all the pieces (both colors)
 /// that are blocking attacks on the square 's' from 'sliders'. A piece blocks a
 /// slider if removing that piece from the board would result in a position where
@@ -429,11 +495,11 @@ Phase Position::game_phase() const {
 
 Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const {
 
-  Bitboard result = 0;
+  Bitboard blockers = 0;
   pinners = 0;
 
   // Snipers are sliders that attack 's' when a piece is removed
-  Bitboard snipers = (  (PseudoAttacks[ROOK  ][s] & pieces(QUEEN, ROOK))
+  Bitboard snipers = (  (PseudoAttacks[  ROOK][s] & pieces(QUEEN, ROOK))
                       | (PseudoAttacks[BISHOP][s] & pieces(QUEEN, BISHOP))) & sliders;
 
   while (snipers)
@@ -441,14 +507,14 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners
     Square sniperSq = pop_lsb(&snipers);
     Bitboard b = between_bb(s, sniperSq) & pieces();
 
-    if (!more_than_one(b))
+    if (b && !more_than_one(b))
     {
-        result |= b;
+        blockers |= b;
         if (b & pieces(color_of(piece_on(s))))
             pinners |= sniperSq;
     }
   }
-  return result;
+  return blockers;
 }
 
 
@@ -460,7 +526,7 @@ Bitboard Position::attackers_to(Square s, Bitboard occupied) const {
   return  (attacks_from<PAWN>(s, BLACK)    & pieces(WHITE, PAWN))
         | (attacks_from<PAWN>(s, WHITE)    & pieces(BLACK, PAWN))
         | (attacks_from<KNIGHT>(s)         & pieces(KNIGHT))
-        | (attacks_bb<ROOK  >(s, occupied) & pieces(ROOK,   QUEEN))
+        | (attacks_bb<  ROOK>(s, occupied) & pieces(  ROOK, QUEEN))
         | (attacks_bb<BISHOP>(s, occupied) & pieces(BISHOP, QUEEN))
         | (attacks_from<KING>(s)           & pieces(KING));
 }
@@ -505,7 +571,7 @@ bool Position::legal(Move m) const {
 
   // A non-king move is legal if and only if it is not pinned or it
   // is moving along the ray towards or away from the king.
-  return   !(pinned_pieces(us) & from)
+  return   !(blockers_for_king(us) & from)
         ||  aligned(from, to_sq(m), square<KING>(us));
 }
 
@@ -554,7 +620,7 @@ bool Position::pseudo_legal(const Move m) const {
                && empty(to - pawn_push(us))))
           return false;
   }
-  else if (!(attacks_from(pc, from) & to))
+  else if (!(attacks_from(type_of(pc), from) & to))
       return false;
 
   // Evasions generator already takes care to avoid some kind of illegal moves
@@ -597,7 +663,7 @@ bool Position::gives_check(Move m) const {
       return true;
 
   // Is there a discovered check?
-  if (   (discovered_check_candidates() & from)
+  if (   (st->blockersForKing[~sideToMove] & from)
       && !aligned(from, to, square<KING>(~sideToMove)))
       return true;
 
@@ -607,7 +673,7 @@ bool Position::gives_check(Move m) const {
       return false;
 
   case PROMOTION:
-      return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & square<KING>(~sideToMove);
+      return attacks_bb(promotion_type(m), to, pieces() ^ from) & square<KING>(~sideToMove);
 
   // En passant capture with check? We have already handled the case
   // of direct checks and ordinary discovered check, so the only case we
@@ -647,7 +713,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
   assert(is_ok(m));
   assert(&newSt != st);
 
-  ++nodes;
+  thisThread->nodes.fetch_add(1, std::memory_order_relaxed);
   Key k = st->key ^ Zobrist::side;
 
   // Copy some fields of the old state to our new StateInfo object except the
@@ -682,7 +748,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       Square rfrom, rto;
       do_castling<true>(us, from, to, rfrom, rto);
 
-      st->psq += PSQT::psq[captured][rto] - PSQT::psq[captured][rfrom];
       k ^= Zobrist::psq[captured][rfrom] ^ Zobrist::psq[captured][rto];
       captured = NO_PIECE;
   }
@@ -721,9 +786,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]];
       prefetch(thisThread->materialTable[st->materialKey]);
 
-      // Update incremental scores
-      st->psq -= PSQT::psq[captured][capsq];
-
       // Reset rule 50 counter
       st->rule50 = 0;
   }
@@ -757,7 +819,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       if (   (int(to) ^ int(from)) == 16
           && (attacks_from<PAWN>(to - pawn_push(us), us) & pieces(them, PAWN)))
       {
-          st->epSquare = (from + to) / 2;
+          st->epSquare = to - pawn_push(us);
           k ^= Zobrist::enpassant[file_of(st->epSquare)];
       }
 
@@ -777,24 +839,18 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
           st->materialKey ^=  Zobrist::psq[promotion][pieceCount[promotion]-1]
                             ^ Zobrist::psq[pc][pieceCount[pc]];
 
-          // Update incremental score
-          st->psq += PSQT::psq[promotion][to] - PSQT::psq[pc][to];
-
           // Update material
           st->nonPawnMaterial[us] += PieceValue[MG][promotion];
       }
 
       // Update pawn hash key and prefetch access to pawnsTable
       st->pawnKey ^= Zobrist::psq[pc][from] ^ Zobrist::psq[pc][to];
-      prefetch(thisThread->pawnsTable[st->pawnKey]);
+      prefetch2(thisThread->pawnsTable[st->pawnKey]);
 
       // Reset rule 50 draw counter
       st->rule50 = 0;
   }
 
-  // Update incremental scores
-  st->psq += PSQT::psq[pc][to] - PSQT::psq[pc][from];
-
   // Set capture piece
   st->capturedPiece = captured;
 
@@ -956,106 +1012,201 @@ Key Position::key_after(Move m) const {
 
 
 /// Position::see_ge (Static Exchange Evaluation Greater or Equal) tests if the
-/// SEE value of move is greater or equal to the given value. We'll use an
+/// SEE value of move is greater or equal to the given threshold. We'll use an
 /// algorithm similar to alpha-beta pruning with a null window.
 
-bool Position::see_ge(Move m, Value v) const {
+bool Position::see_ge(Move m, Value threshold) const {
 
   assert(is_ok(m));
 
-  // Castling moves are implemented as king capturing the rook so cannot be
-  // handled correctly. Simply assume the SEE value is VALUE_ZERO that is always
-  // correct unless in the rare case the rook ends up under attack.
-  if (type_of(m) == CASTLING)
-      return VALUE_ZERO >= v;
+  // Only deal with normal moves, assume others pass a simple see
+  if (type_of(m) != NORMAL)
+      return VALUE_ZERO >= threshold;
 
+  Bitboard stmAttackers;
   Square from = from_sq(m), to = to_sq(m);
   PieceType nextVictim = type_of(piece_on(from));
-  Color stm = ~color_of(piece_on(from)); // First consider opponent's move
-  Value balance; // Values of the pieces taken by us minus opponent's ones
-  Bitboard occupied, stmAttackers;
+  Color us = color_of(piece_on(from));
+  Color stm = ~us; // First consider opponent's move
+  Value balance;   // Values of the pieces taken by us minus opponent's ones
 
-  if (type_of(m) == ENPASSANT)
-  {
-      occupied = SquareBB[to - pawn_push(~stm)]; // Remove the captured pawn
-      balance = PieceValue[MG][PAWN];
-  }
-  else
-  {
-      balance = PieceValue[MG][piece_on(to)];
-      occupied = 0;
-  }
+  // The opponent may be able to recapture so this is the best result
+  // we can hope for.
+  balance = PieceValue[MG][piece_on(to)] - threshold;
 
-  if (balance < v)
+  if (balance < VALUE_ZERO)
       return false;
 
-  if (nextVictim == KING)
-      return true;
-
+  // Now assume the worst possible result: that the opponent can
+  // capture our piece for free.
   balance -= PieceValue[MG][nextVictim];
 
-  if (balance >= v)
+  // If it is enough (like in PxQ) then return immediately. Note that
+  // in case nextVictim == KING we always return here, this is ok
+  // if the given move is legal.
+  if (balance >= VALUE_ZERO)
       return true;
 
-  bool relativeStm = true; // True if the opponent is to move
-  occupied ^= pieces() ^ from ^ to;
-
-  // Find all attackers to the destination square, with the moving piece removed,
-  // but possibly an X-ray attacker added behind it.
+  // Find all attackers to the destination square, with the moving piece
+  // removed, but possibly an X-ray attacker added behind it.
+  Bitboard occupied = pieces() ^ from ^ to;
   Bitboard attackers = attackers_to(to, occupied) & occupied;
 
   while (true)
   {
       stmAttackers = attackers & pieces(stm);
 
-      // Don't allow pinned pieces to attack pieces except the king as long all
-      // pinners are on their original square.
-      if (!(st->pinnersForKing[stm] & ~occupied))
+      // Don't allow pinned pieces to attack (except the king) as long as
+      // all pinners are on their original square.
+      if (!(st->pinners[~stm] & ~occupied))
           stmAttackers &= ~st->blockersForKing[stm];
 
+      // If stm has no more attackers then give up: stm loses
       if (!stmAttackers)
-          return relativeStm;
+          break;
 
-      // Locate and remove the next least valuable attacker
+      // Locate and remove the next least valuable attacker, and add to
+      // the bitboard 'attackers' the possibly X-ray attackers behind it.
       nextVictim = min_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers);
 
-      if (nextVictim == KING)
-          return relativeStm == bool(attackers & pieces(~stm));
+      stm = ~stm; // Switch side to move
 
-      balance += relativeStm ?  PieceValue[MG][nextVictim]
-                             : -PieceValue[MG][nextVictim];
+      // Negamax the balance with alpha = balance, beta = balance+1 and
+      // add nextVictim's value.
+      //
+      //      (balance, balance+1) -> (-balance-1, -balance)
+      //
+      assert(balance < VALUE_ZERO);
 
-      relativeStm = !relativeStm;
+      balance = -balance - 1 - PieceValue[MG][nextVictim];
 
-      if (relativeStm == (balance >= v))
-          return relativeStm;
-
-      stm = ~stm;
+      // If balance is still non-negative after giving away nextVictim then we
+      // win. The only thing to be careful about it is that we should revert
+      // stm if we captured with the king when the opponent still has attackers.
+      if (balance >= VALUE_ZERO)
+      {
+          if (nextVictim == KING && (attackers & pieces(stm)))
+              stm = ~stm;
+          break;
+      }
+      assert(nextVictim != KING);
   }
+  return us != stm; // We break the above loop when stm loses
 }
 
 
 /// Position::is_draw() tests whether the position is drawn by 50-move rule
 /// or by repetition. It does not detect stalemates.
 
-bool Position::is_draw() const {
+bool Position::is_draw(int ply) const {
 
   if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
       return true;
 
-  StateInfo* stp = st;
-  for (int i = 2, e = std::min(st->rule50, st->pliesFromNull); i <= e; i += 2)
+  int end = std::min(st->rule50, st->pliesFromNull);
+
+  if (end < 4)
+    return false;
+
+  StateInfo* stp = st->previous->previous;
+  int cnt = 0;
+
+  for (int i = 4; i <= end; i += 2)
   {
       stp = stp->previous->previous;
 
-      if (stp->key == st->key)
-          return true; // Draw at first repetition
+      // Return a draw score if a position repeats once earlier but strictly
+      // after the root, or repeats twice before or at the root.
+      if (   stp->key == st->key
+          && ++cnt + (ply > i) == 2)
+          return true;
   }
 
   return false;
 }
 
 
+// Position::has_repeated() tests whether there has been at least one repetition
+// of positions since the last capture or pawn move.
+
+bool Position::has_repeated() const {
+
+    StateInfo* stc = st;
+    while (true)
+    {
+        int i = 4, end = std::min(stc->rule50, stc->pliesFromNull);
+
+        if (end < i)
+            return false;
+
+        StateInfo* stp = stc->previous->previous;
+
+        do {
+            stp = stp->previous->previous;
+
+            if (stp->key == stc->key)
+                return true;
+
+            i += 2;
+        } while (i <= end);
+
+        stc = stc->previous;
+    }
+}
+
+
+/// Position::has_game_cycle() tests if the position has a move which draws by repetition,
+/// or an earlier position has a move that directly reaches the current position.
+
+bool Position::has_game_cycle(int ply) const {
+
+  int j;
+
+  int end = std::min(st->rule50, st->pliesFromNull);
+
+  if (end < 3)
+    return false;
+
+  Key originalKey = st->key;
+  StateInfo* stp = st->previous;
+
+  for (int i = 3; i <= end; i += 2)
+  {
+      stp = stp->previous->previous;
+
+      Key moveKey = originalKey ^ stp->key;
+      if (   (j = H1(moveKey), cuckoo[j] == moveKey)
+          || (j = H2(moveKey), cuckoo[j] == moveKey))
+      {
+          Move move = cuckooMove[j];
+          Square s1 = from_sq(move);
+          Square s2 = to_sq(move);
+
+          if (!(between_bb(s1, s2) & pieces()))
+          {
+              // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in the same
+              // location. We select the legal one by reversing the move variable if necessary.
+              if (empty(s1))
+                  move = make_move(s2, s1);
+
+              if (ply > i)
+                  return true;
+
+              // For repetitions before or at the root, require one more
+              StateInfo* next_stp = stp;
+              for (int k = i + 2; k <= end; k += 2)
+              {
+                  next_stp = next_stp->previous->previous;
+                  if (next_stp->key == stp->key)
+                     return true;
+              }
+          }
+      }
+  }
+  return false;
+}
+
+
 /// Position::flip() flips position with the white and black sides reversed. This
 /// is only useful for debugging e.g. for finding evaluation symmetry bugs.
 
@@ -1091,78 +1242,72 @@ void Position::flip() {
 }
 
 
-/// Position::pos_is_ok() performs some consistency checks for the position object.
+/// Position::pos_is_ok() performs some consistency checks for the
+/// position object and raises an asserts if something wrong is detected.
 /// This is meant to be helpful when debugging.
 
-bool Position::pos_is_ok(int* failedStep) const {
+bool Position::pos_is_ok() const {
 
-  const bool Fast = true; // Quick (default) or full check?
+  constexpr bool Fast = true; // Quick (default) or full check?
 
-  enum { Default, King, Bitboards, State, Lists, Castling };
+  if (   (sideToMove != WHITE && sideToMove != BLACK)
+      || piece_on(square<KING>(WHITE)) != W_KING
+      || piece_on(square<KING>(BLACK)) != B_KING
+      || (   ep_square() != SQ_NONE
+          && relative_rank(sideToMove, ep_square()) != RANK_6))
+      assert(0 && "pos_is_ok: Default");
 
-  for (int step = Default; step <= (Fast ? Default : Castling); step++)
+  if (Fast)
+      return true;
+
+  if (   pieceCount[W_KING] != 1
+      || pieceCount[B_KING] != 1
+      || attackers_to(square<KING>(~sideToMove)) & pieces(sideToMove))
+      assert(0 && "pos_is_ok: Kings");
+
+  if (   (pieces(PAWN) & (Rank1BB | Rank8BB))
+      || pieceCount[W_PAWN] > 8
+      || pieceCount[B_PAWN] > 8)
+      assert(0 && "pos_is_ok: Pawns");
+
+  if (   (pieces(WHITE) & pieces(BLACK))
+      || (pieces(WHITE) | pieces(BLACK)) != pieces()
+      || popcount(pieces(WHITE)) > 16
+      || popcount(pieces(BLACK)) > 16)
+      assert(0 && "pos_is_ok: Bitboards");
+
+  for (PieceType p1 = PAWN; p1 <= KING; ++p1)
+      for (PieceType p2 = PAWN; p2 <= KING; ++p2)
+          if (p1 != p2 && (pieces(p1) & pieces(p2)))
+              assert(0 && "pos_is_ok: Bitboards");
+
+  StateInfo si = *st;
+  set_state(&si);
+  if (std::memcmp(&si, st, sizeof(StateInfo)))
+      assert(0 && "pos_is_ok: State");
+
+  for (Piece pc : Pieces)
   {
-      if (failedStep)
-          *failedStep = step;
+      if (   pieceCount[pc] != popcount(pieces(color_of(pc), type_of(pc)))
+          || pieceCount[pc] != std::count(board, board + SQUARE_NB, pc))
+          assert(0 && "pos_is_ok: Pieces");
 
-      if (step == Default)
-          if (   (sideToMove != WHITE && sideToMove != BLACK)
-              || piece_on(square<KING>(WHITE)) != W_KING
-              || piece_on(square<KING>(BLACK)) != B_KING
-              || (   ep_square() != SQ_NONE
-                  && relative_rank(sideToMove, ep_square()) != RANK_6))
-              return false;
-
-      if (step == King)
-          if (   std::count(board, board + SQUARE_NB, W_KING) != 1
-              || std::count(board, board + SQUARE_NB, B_KING) != 1
-              || attackers_to(square<KING>(~sideToMove)) & pieces(sideToMove))
-              return false;
-
-      if (step == Bitboards)
-      {
-          if (  (pieces(WHITE) & pieces(BLACK))
-              ||(pieces(WHITE) | pieces(BLACK)) != pieces())
-              return false;
-
-          for (PieceType p1 = PAWN; p1 <= KING; ++p1)
-              for (PieceType p2 = PAWN; p2 <= KING; ++p2)
-                  if (p1 != p2 && (pieces(p1) & pieces(p2)))
-                      return false;
-      }
-
-      if (step == State)
-      {
-          StateInfo si = *st;
-          set_state(&si);
-          if (std::memcmp(&si, st, sizeof(StateInfo)))
-              return false;
-      }
-
-      if (step == Lists)
-          for (Piece pc : Pieces)
-          {
-              if (pieceCount[pc] != popcount(pieces(color_of(pc), type_of(pc))))
-                  return false;
-
-              for (int i = 0; i < pieceCount[pc]; ++i)
-                  if (board[pieceList[pc][i]] != pc || index[pieceList[pc][i]] != i)
-                      return false;
-          }
-
-      if (step == Castling)
-          for (Color c = WHITE; c <= BLACK; ++c)
-              for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1))
-              {
-                  if (!can_castle(c | s))
-                      continue;
-
-                  if (   piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK)
-                      || castlingRightsMask[castlingRookSquare[c | s]] != (c | s)
-                      ||(castlingRightsMask[square<KING>(c)] & (c | s)) != (c | s))
-                      return false;
-              }
+      for (int i = 0; i < pieceCount[pc]; ++i)
+          if (board[pieceList[pc][i]] != pc || index[pieceList[pc][i]] != i)
+              assert(0 && "pos_is_ok: Index");
   }
 
+  for (Color c = WHITE; c <= BLACK; ++c)
+      for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1))
+      {
+          if (!can_castle(c | s))
+              continue;
+
+          if (   piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK)
+              || castlingRightsMask[castlingRookSquare[c | s]] != (c | s)
+              || (castlingRightsMask[square<KING>(c)] & (c | s)) != (c | s))
+              assert(0 && "pos_is_ok: Castling");
+      }
+
   return true;
 }

src/position.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -43,7 +43,6 @@ struct StateInfo {
   int    castlingRights;
   int    rule50;
   int    pliesFromNull;
-  Score  psq;
   Square epSquare;
 
   // Not copied when making a move (will be recomputed anyhow)
@@ -52,11 +51,14 @@ struct StateInfo {
   Piece      capturedPiece;
   StateInfo* previous;
   Bitboard   blockersForKing[COLOR_NB];
-  Bitboard   pinnersForKing[COLOR_NB];
+  Bitboard   pinners[COLOR_NB];
   Bitboard   checkSquares[PIECE_TYPE_NB];
 };
 
-// In a std::deque references to elements are unaffected upon resizing
+/// A list to keep track of the position states along the setup moves (from the
+/// start position to the position just before the search starts). Needed by
+/// 'draw by repetition' detection. Use a std::deque because pointers to
+/// elements are not invalidated upon list resizing.
 typedef std::unique_ptr<std::deque<StateInfo>> StateListPtr;
 
 
@@ -76,6 +78,7 @@ public:
 
   // FEN string input/output
   Position& set(const std::string& fenStr, bool isChess960, StateInfo* si, Thread* th);
+  Position& set(const std::string& code, Color c, StateInfo* si);
   const std::string fen() const;
 
   // Position representation
@@ -89,6 +92,7 @@ public:
   Square ep_square() const;
   bool empty(Square s) const;
   template<PieceType Pt> int count(Color c) const;
+  template<PieceType Pt> int count() const;
   template<PieceType Pt> const Square* squares(Color c) const;
   template<PieceType Pt> Square square(Color c) const;
 
@@ -100,14 +104,13 @@ public:
 
   // Checking
   Bitboard checkers() const;
-  Bitboard discovered_check_candidates() const;
-  Bitboard pinned_pieces(Color c) const;
+  Bitboard blockers_for_king(Color c) const;
   Bitboard check_squares(PieceType pt) const;
 
   // Attacks to/from a given square
   Bitboard attackers_to(Square s) const;
   Bitboard attackers_to(Square s, Bitboard occupied) const;
-  Bitboard attacks_from(Piece pc, Square s) const;
+  Bitboard attacks_from(PieceType pt, Square s) const;
   template<PieceType> Bitboard attacks_from(Square s) const;
   template<PieceType> Bitboard attacks_from(Square s, Color c) const;
   Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const;
@@ -127,13 +130,14 @@ public:
   bool opposite_bishops() const;
 
   // Doing and undoing moves
-  void do_move(Move m, StateInfo& st, bool givesCheck);
+  void do_move(Move m, StateInfo& newSt);
+  void do_move(Move m, StateInfo& newSt, bool givesCheck);
   void undo_move(Move m);
-  void do_null_move(StateInfo& st);
+  void do_null_move(StateInfo& newSt);
   void undo_null_move();
 
   // Static Exchange Evaluation
-  bool see_ge(Move m, Value value) const;
+  bool see_ge(Move m, Value threshold = VALUE_ZERO) const;
 
   // Accessing hash keys
   Key key() const;
@@ -143,18 +147,19 @@ public:
 
   // Other properties of the position
   Color side_to_move() const;
-  Phase game_phase() const;
   int game_ply() const;
   bool is_chess960() const;
   Thread* this_thread() const;
-  uint64_t nodes_searched() const;
-  bool is_draw() const;
+  bool is_draw(int ply) const;
+  bool has_game_cycle(int ply) const;
+  bool has_repeated() const;
   int rule50_count() const;
   Score psq_score() const;
   Value non_pawn_material(Color c) const;
+  Value non_pawn_material() const;
 
   // Position consistency check, for debugging
-  bool pos_is_ok(int* failedStep = nullptr) const;
+  bool pos_is_ok() const;
   void flip();
 
 private:
@@ -180,14 +185,18 @@ private:
   int castlingRightsMask[SQUARE_NB];
   Square castlingRookSquare[CASTLING_RIGHT_NB];
   Bitboard castlingPath[CASTLING_RIGHT_NB];
-  uint64_t nodes;
   int gamePly;
   Color sideToMove;
+  Score psq;
   Thread* thisThread;
   StateInfo* st;
   bool chess960;
 };
 
+namespace PSQT {
+  extern Score psq[PIECE_NB][SQUARE_NB];
+}
+
 extern std::ostream& operator<<(std::ostream& os, const Position& pos);
 
 inline Color Position::side_to_move() const {
@@ -234,6 +243,10 @@ template<PieceType Pt> inline int Position::count(Color c) const {
   return pieceCount[make_piece(c, Pt)];
 }
 
+template<PieceType Pt> inline int Position::count() const {
+  return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)];
+}
+
 template<PieceType Pt> inline const Square* Position::squares(Color c) const {
   return pieceList[make_piece(c, Pt)];
 }
@@ -265,18 +278,19 @@ inline Square Position::castling_rook_square(CastlingRight cr) const {
 
 template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
+  assert(Pt != PAWN);
   return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, byTypeBB[ALL_PIECES])
         : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
-        : StepAttacksBB[Pt][s];
+        : PseudoAttacks[Pt][s];
 }
 
 template<>
 inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
-  return StepAttacksBB[make_piece(c, PAWN)][s];
+  return PawnAttacks[c][s];
 }
 
-inline Bitboard Position::attacks_from(Piece pc, Square s) const {
-  return attacks_bb(pc, s, byTypeBB[ALL_PIECES]);
+inline Bitboard Position::attacks_from(PieceType pt, Square s) const {
+  return attacks_bb(pt, s, byTypeBB[ALL_PIECES]);
 }
 
 inline Bitboard Position::attackers_to(Square s) const {
@@ -287,12 +301,8 @@ inline Bitboard Position::checkers() const {
   return st->checkersBB;
 }
 
-inline Bitboard Position::discovered_check_candidates() const {
-  return st->blockersForKing[~sideToMove] & pieces(sideToMove);
-}
-
-inline Bitboard Position::pinned_pieces(Color c) const {
-  return st->blockersForKing[c] & pieces(c);
+inline Bitboard Position::blockers_for_king(Color c) const {
+  return st->blockersForKing[c];
 }
 
 inline Bitboard Position::check_squares(PieceType pt) const {
@@ -321,13 +331,17 @@ inline Key Position::material_key() const {
 }
 
 inline Score Position::psq_score() const {
-  return st->psq;
+  return psq;
 }
 
 inline Value Position::non_pawn_material(Color c) const {
   return st->nonPawnMaterial[c];
 }
 
+inline Value Position::non_pawn_material() const {
+  return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK];
+}
+
 inline int Position::game_ply() const {
   return gamePly;
 }
@@ -336,10 +350,6 @@ inline int Position::rule50_count() const {
   return st->rule50;
 }
 
-inline uint64_t Position::nodes_searched() const {
-  return nodes;
-}
-
 inline bool Position::opposite_bishops() const {
   return   pieceCount[W_BISHOP] == 1
         && pieceCount[B_BISHOP] == 1
@@ -378,6 +388,7 @@ inline void Position::put_piece(Piece pc, Square s) {
   index[s] = pieceCount[pc]++;
   pieceList[pc][index[s]] = s;
   pieceCount[make_piece(color_of(pc), ALL_PIECES)]++;
+  psq += PSQT::psq[pc][s];
 }
 
 inline void Position::remove_piece(Piece pc, Square s) {
@@ -395,20 +406,26 @@ inline void Position::remove_piece(Piece pc, Square s) {
   pieceList[pc][index[lastSquare]] = lastSquare;
   pieceList[pc][pieceCount[pc]] = SQ_NONE;
   pieceCount[make_piece(color_of(pc), ALL_PIECES)]--;
+  psq -= PSQT::psq[pc][s];
 }
 
 inline void Position::move_piece(Piece pc, Square from, Square to) {
 
   // index[from] is not updated and becomes stale. This works as long as index[]
   // is accessed just by known occupied squares.
-  Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
-  byTypeBB[ALL_PIECES] ^= from_to_bb;
-  byTypeBB[type_of(pc)] ^= from_to_bb;
-  byColorBB[color_of(pc)] ^= from_to_bb;
+  Bitboard fromTo = SquareBB[from] ^ SquareBB[to];
+  byTypeBB[ALL_PIECES] ^= fromTo;
+  byTypeBB[type_of(pc)] ^= fromTo;
+  byColorBB[color_of(pc)] ^= fromTo;
   board[from] = NO_PIECE;
   board[to] = pc;
   index[to] = index[from];
   pieceList[pc][index[to]] = to;
+  psq += PSQT::psq[pc][to] - PSQT::psq[pc][from];
+}
+
+inline void Position::do_move(Move m, StateInfo& newSt) {
+  do_move(m, newSt, gives_check(m));
 }
 
 #endif // #ifndef POSITION_H_INCLUDED

src/psqt.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -35,66 +35,66 @@ namespace PSQT {
 // type on a given square a (middlegame, endgame) score pair is assigned. Table
 // is defined for files A..D and white side: it is symmetric for black side and
 // second half of the files.
-const Score Bonus[][RANK_NB][int(FILE_NB) / 2] = {
+constexpr Score Bonus[][RANK_NB][int(FILE_NB) / 2] = {
   { },
   { // Pawn
-   { S(  0, 0), S(  0, 0), S(  0, 0), S( 0, 0) },
-   { S(-16, 7), S(  1,-4), S(  7, 8), S( 3,-2) },
-   { S(-23,-4), S( -7,-5), S( 19, 5), S(24, 4) },
-   { S(-22, 3), S(-14, 3), S( 20,-8), S(35,-3) },
-   { S(-11, 8), S(  0, 9), S(  3, 7), S(21,-6) },
-   { S(-11, 8), S(-13,-5), S( -6, 2), S(-2, 4) },
-   { S( -9, 3), S( 15,-9), S( -8, 1), S(-4,18) }
+   { S(  0, 0), S(  0,  0), S(  0, 0), S( 0, 0) },
+   { S(-11,-3), S(  7, -1), S(  7, 7), S(17, 2) },
+   { S(-16,-2), S( -3,  2), S( 23, 6), S(23,-1) },
+   { S(-14, 7), S( -7, -4), S( 20,-8), S(24, 2) },
+   { S( -5,13), S( -2, 10), S( -1,-1), S(12,-8) },
+   { S(-11,16), S(-12,  6), S( -2, 1), S( 4,16) },
+   { S( -2, 1), S( 20,-12), S(-10, 6), S(-2,25) }
   },
   { // Knight
-   { S(-143, -97), S(-96,-82), S(-80,-46), S(-73,-14) },
-   { S( -83, -69), S(-43,-55), S(-21,-17), S(-10,  9) },
-   { S( -71, -50), S(-22,-39), S(  0, -8), S(  9, 28) },
-   { S( -25, -41), S( 18,-25), S( 43,  7), S( 47, 38) },
-   { S( -26, -46), S( 16,-25), S( 38,  2), S( 50, 41) },
-   { S( -11, -55), S( 37,-38), S( 56, -8), S( 71, 27) },
-   { S( -62, -64), S(-17,-50), S(  5,-24), S( 14, 13) },
-   { S(-195,-110), S(-66,-90), S(-42,-50), S(-29,-13) }
+   { S(-169,-105), S(-96,-74), S(-80,-46), S(-79,-18) },
+   { S( -79, -70), S(-39,-56), S(-24,-15), S( -9,  6) },
+   { S( -64, -38), S(-20,-33), S(  4, -5), S( 19, 27) },
+   { S( -28, -36), S(  5,  0), S( 41, 13), S( 47, 34) },
+   { S( -29, -41), S( 13,-20), S( 42,  4), S( 52, 35) },
+   { S( -11, -51), S( 28,-38), S( 63,-17), S( 55, 19) },
+   { S( -67, -64), S(-21,-45), S(  6,-37), S( 37, 16) },
+   { S(-200, -98), S(-80,-89), S(-53,-53), S(-32,-16) }
   },
   { // Bishop
-   { S(-54,-68), S(-23,-40), S(-35,-46), S(-44,-28) },
-   { S(-30,-43), S( 10,-17), S(  2,-23), S( -9, -5) },
-   { S(-19,-32), S( 17, -9), S( 11,-13), S(  1,  8) },
-   { S(-21,-36), S( 18,-13), S( 11,-15), S(  0,  7) },
-   { S(-21,-36), S( 14,-14), S(  6,-17), S( -1,  3) },
-   { S(-27,-35), S(  6,-13), S(  2,-10), S( -8,  1) },
-   { S(-33,-44), S(  7,-21), S( -4,-22), S(-12, -4) },
-   { S(-45,-65), S(-21,-42), S(-29,-46), S(-39,-27) }
+   { S(-49,-58), S(- 7,-31), S(-10,-37), S(-34,-19) },
+   { S(-24,-34), S(  9, -9), S( 15,-14), S(  1,  4) },
+   { S( -9,-23), S( 22,  0), S( -3, -3), S( 12, 16) },
+   { S(  4,-26), S(  9, -3), S( 18, -5), S( 40, 16) },
+   { S( -8,-26), S( 27, -4), S( 13, -7), S( 30, 14) },
+   { S(-17,-24), S( 14, -2), S( -6,  0), S(  6, 13) },
+   { S(-19,-34), S(-13,-10), S(  7,-12), S(-11,  6) },
+   { S(-47,-55), S( -7,-32), S(-17,-36), S(-29,-17) }
   },
   { // Rook
-   { S(-25, 0), S(-16, 0), S(-16, 0), S(-9, 0) },
-   { S(-21, 0), S( -8, 0), S( -3, 0), S( 0, 0) },
-   { S(-21, 0), S( -9, 0), S( -4, 0), S( 2, 0) },
-   { S(-22, 0), S( -6, 0), S( -1, 0), S( 2, 0) },
-   { S(-22, 0), S( -7, 0), S(  0, 0), S( 1, 0) },
-   { S(-21, 0), S( -7, 0), S(  0, 0), S( 2, 0) },
-   { S(-12, 0), S(  4, 0), S(  8, 0), S(12, 0) },
-   { S(-23, 0), S(-15, 0), S(-11, 0), S(-5, 0) }
+   { S(-24, 0), S(-15, 3), S( -8, 0), S( 0, 3) },
+   { S(-18,-7), S( -5,-5), S( -1,-5), S( 1,-1) },
+   { S(-19, 6), S(-10,-7), S(  1, 3), S( 0, 3) },
+   { S(-21, 0), S( -7, 4), S( -4,-2), S(-4, 1) },
+   { S(-21,-7), S(-12, 5), S( -1,-5), S( 4,-7) },
+   { S(-23, 3), S(-10, 2), S(  1,-1), S( 6, 3) },
+   { S(-11,-1), S(  8, 7), S(  9,11), S(12,-1) },
+   { S(-25, 6), S(-18, 4), S(-11, 6), S( 2, 2) }
   },
   { // Queen
-   { S( 0,-70), S(-3,-57), S(-4,-41), S(-1,-29) },
-   { S(-4,-58), S( 6,-30), S( 9,-21), S( 8, -4) },
-   { S(-2,-39), S( 6,-17), S( 9, -7), S( 9,  5) },
-   { S(-1,-29), S( 8, -5), S(10,  9), S( 7, 17) },
-   { S(-3,-27), S( 9, -5), S( 8, 10), S( 7, 23) },
-   { S(-2,-40), S( 6,-16), S( 8,-11), S(10,  3) },
-   { S(-2,-54), S( 7,-30), S( 7,-21), S( 6, -7) },
-   { S(-1,-75), S(-4,-54), S(-1,-44), S( 0,-30) }
+   { S(  3,-69), S(-5,-57), S(-5,-47), S( 4,-26) },
+   { S( -3,-55), S( 5,-31), S( 8,-22), S(12, -4) },
+   { S( -3,-39), S( 6,-18), S(13, -9), S( 7,  3) },
+   { S(  4,-23), S( 5, -3), S( 9, 13), S( 8, 24) },
+   { S(  0,-29), S(14, -6), S(12,  9), S( 5, 21) },
+   { S( -4,-38), S(10,-18), S( 6,-12), S( 8,  1) },
+   { S( -5,-50), S( 6,-27), S(10,-24), S( 8, -8) },
+   { S( -2,-75), S(-2,-52), S( 1,-43), S(-2,-36) }
   },
   { // King
-   { S(291, 28), S(344, 76), S(294,103), S(219,112) },
-   { S(289, 70), S(329,119), S(263,170), S(205,159) },
-   { S(226,109), S(271,164), S(202,195), S(136,191) },
-   { S(204,131), S(212,194), S(175,194), S(137,204) },
-   { S(177,132), S(205,187), S(143,224), S( 94,227) },
-   { S(147,118), S(188,178), S(113,199), S( 70,197) },
-   { S(116, 72), S(158,121), S( 93,142), S( 48,161) },
-   { S( 94, 30), S(120, 76), S( 78,101), S( 31,111) }
+   { S(272,  0), S(325, 41), S(273, 80), S(190, 93) },
+   { S(277, 57), S(305, 98), S(241,138), S(183,131) },
+   { S(198, 86), S(253,138), S(168,165), S(120,173) },
+   { S(169,103), S(191,152), S(136,168), S(108,169) },
+   { S(145, 98), S(176,166), S(112,197), S(69, 194) },
+   { S(122, 87), S(159,164), S(85, 174), S(36, 189) },
+   { S(87,  40), S(120, 99), S(64, 128), S(25, 141) },
+   { S(64,   5), S(87,  60), S(49,  75), S(0,   75) }
   }
 };
 
@@ -112,12 +112,12 @@ void init() {
       PieceValue[MG][~pc] = PieceValue[MG][pc];
       PieceValue[EG][~pc] = PieceValue[EG][pc];
 
-      Score v = make_score(PieceValue[MG][pc], PieceValue[EG][pc]);
+      Score score = make_score(PieceValue[MG][pc], PieceValue[EG][pc]);
 
       for (Square s = SQ_A1; s <= SQ_H8; ++s)
       {
-          File f = std::min(file_of(s), FILE_H - file_of(s));
-          psq[ pc][ s] = v + Bonus[pc][rank_of(s)][f];
+          File f = std::min(file_of(s), ~file_of(s));
+          psq[ pc][ s] = score + Bonus[pc][rank_of(s)][f];
           psq[~pc][~s] = -psq[pc][s];
       }
   }

src/search.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -21,7 +21,6 @@
 #ifndef SEARCH_H_INCLUDED
 #define SEARCH_H_INCLUDED
 
-#include <atomic>
 #include <vector>
 
 #include "misc.h"
@@ -32,21 +31,24 @@ class Position;
 
 namespace Search {
 
+/// Threshold used for countermoves based pruning
+constexpr int CounterMovePruneThreshold = 0;
+
+
 /// Stack struct keeps track of the information we need to remember from nodes
 /// shallower and deeper in the tree during the search. Each search thread has
 /// its own array of Stack objects, indexed by the current ply.
 
 struct Stack {
   Move* pv;
+  PieceToHistory* continuationHistory;
   int ply;
   Move currentMove;
   Move excludedMove;
   Move killers[2];
   Value staticEval;
-  Value history;
-  bool skipEarlyPruning;
+  int statScore;
   int moveCount;
-  CounterMoveStats* counterMoves;
 };
 
 
@@ -57,13 +59,18 @@ struct Stack {
 struct RootMove {
 
   explicit RootMove(Move m) : pv(1, m) {}
-
-  bool operator<(const RootMove& m) const { return m.score < score; } // Descending sort
-  bool operator==(const Move& m) const { return pv[0] == m; }
   bool extract_ponder_from_tt(Position& pos);
+  bool operator==(const Move& m) const { return pv[0] == m; }
+  bool operator<(const RootMove& m) const { // Sort in descending order
+    return m.score != score ? m.score < score
+                            : m.previousScore < previousScore;
+  }
 
   Value score = -VALUE_INFINITE;
   Value previousScore = -VALUE_INFINITE;
+  int selDepth = 0;
+  int tbRank;
+  Value tbScore;
   std::vector<Move> pv;
 };
 
@@ -71,40 +78,30 @@ typedef std::vector<RootMove> RootMoves;
 
 
 /// LimitsType struct stores information sent by GUI about available time to
-/// search the current move, maximum depth/time, if we are in analysis mode or
-/// if we have to ponder while it's our opponent's turn to move.
+/// search the current move, maximum depth/time, or if we are in analysis mode.
 
 struct LimitsType {
 
   LimitsType() { // Init explicitly due to broken value-initialization of non POD in MSVC
-    nodes = time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] =
-    npmsec = movestogo = depth = movetime = mate = infinite = ponder = 0;
+    time[WHITE] = time[BLACK] = inc[WHITE] = inc[BLACK] = npmsec = movetime = TimePoint(0);
+    movestogo = depth = mate = perft = infinite = 0;
+    nodes = 0;
   }
 
   bool use_time_management() const {
-    return !(mate | movetime | depth | nodes | infinite);
+    return !(mate | movetime | depth | nodes | perft | infinite);
   }
 
   std::vector<Move> searchmoves;
-  int time[COLOR_NB], inc[COLOR_NB], npmsec, movestogo, depth, movetime, mate, infinite, ponder;
+  TimePoint time[COLOR_NB], inc[COLOR_NB], npmsec, movetime, startTime;
+  int movestogo, depth, mate, perft, infinite;
   int64_t nodes;
-  TimePoint startTime;
 };
 
-
-/// SignalsType struct stores atomic flags updated during the search, typically
-/// in an async fashion e.g. to stop the search by the GUI.
-
-struct SignalsType {
-  std::atomic_bool stop, stopOnPonderhit;
-};
-
-extern SignalsType Signals;
 extern LimitsType Limits;
 
 void init();
 void clear();
-template<bool Root = true> uint64_t perft(Position& pos, Depth depth);
 
 } // namespace Search
 

src/syzygy/tbcore.h

@@ -1,169 +0,0 @@
-/*
-  Copyright (c) 2011-2013 Ronald de Man
-*/
-
-#ifndef TBCORE_H
-#define TBCORE_H
-
-#ifndef _WIN32
-#include <pthread.h>
-#define SEP_CHAR ':'
-#define FD int
-#define FD_ERR -1
-#else
-#include <windows.h>
-#define SEP_CHAR ';'
-#define FD HANDLE
-#define FD_ERR INVALID_HANDLE_VALUE
-#endif
-
-#ifndef _WIN32
-#define LOCK_T pthread_mutex_t
-#define LOCK_INIT(x) pthread_mutex_init(&(x), NULL)
-#define LOCK(x) pthread_mutex_lock(&(x))
-#define UNLOCK(x) pthread_mutex_unlock(&(x))
-#else
-#define LOCK_T HANDLE
-#define LOCK_INIT(x) do { x = CreateMutex(NULL, FALSE, NULL); } while (0)
-#define LOCK(x) WaitForSingleObject(x, INFINITE)
-#define UNLOCK(x) ReleaseMutex(x)
-#endif
-
-#ifndef _MSC_VER
-#define BSWAP32(v) __builtin_bswap32(v)
-#define BSWAP64(v) __builtin_bswap64(v)
-#else
-#define BSWAP32(v) _byteswap_ulong(v)
-#define BSWAP64(v) _byteswap_uint64(v)
-#endif
-
-#define WDLSUFFIX ".rtbw"
-#define DTZSUFFIX ".rtbz"
-#define WDLDIR "RTBWDIR"
-#define DTZDIR "RTBZDIR"
-#define TBPIECES 6
-
-typedef unsigned long long uint64;
-typedef unsigned int uint32;
-typedef unsigned char ubyte;
-typedef unsigned short ushort;
-
-const ubyte WDL_MAGIC[4] = { 0x71, 0xe8, 0x23, 0x5d };
-const ubyte DTZ_MAGIC[4] = { 0xd7, 0x66, 0x0c, 0xa5 };
-
-#define TBHASHBITS 10
-
-struct TBHashEntry;
-
-typedef uint64 base_t;
-
-struct PairsData {
-  char *indextable;
-  ushort *sizetable;
-  ubyte *data;
-  ushort *offset;
-  ubyte *symlen;
-  ubyte *sympat;
-  int blocksize;
-  int idxbits;
-  int min_len;
-  base_t base[1]; // C++ complains about base[]...
-};
-
-struct TBEntry {
-  char *data;
-  uint64 key;
-  uint64 mapping;
-  ubyte ready;
-  ubyte num;
-  ubyte symmetric;
-  ubyte has_pawns;
-}
-#ifndef _WIN32
-__attribute__((__may_alias__))
-#endif
-;
-
-struct TBEntry_piece {
-  char *data;
-  uint64 key;
-  uint64 mapping;
-  ubyte ready;
-  ubyte num;
-  ubyte symmetric;
-  ubyte has_pawns;
-  ubyte enc_type;
-  struct PairsData *precomp[2];
-  int factor[2][TBPIECES];
-  ubyte pieces[2][TBPIECES];
-  ubyte norm[2][TBPIECES];
-};
-
-struct TBEntry_pawn {
-  char *data;
-  uint64 key;
-  uint64 mapping;
-  ubyte ready;
-  ubyte num;
-  ubyte symmetric;
-  ubyte has_pawns;
-  ubyte pawns[2];
-  struct {
-    struct PairsData *precomp[2];
-    int factor[2][TBPIECES];
-    ubyte pieces[2][TBPIECES];
-    ubyte norm[2][TBPIECES];
-  } file[4];
-};
-
-struct DTZEntry_piece {
-  char *data;
-  uint64 key;
-  uint64 mapping;
-  ubyte ready;
-  ubyte num;
-  ubyte symmetric;
-  ubyte has_pawns;
-  ubyte enc_type;
-  struct PairsData *precomp;
-  int factor[TBPIECES];
-  ubyte pieces[TBPIECES];
-  ubyte norm[TBPIECES];
-  ubyte flags; // accurate, mapped, side
-  ushort map_idx[4];
-  ubyte *map;
-};
-
-struct DTZEntry_pawn {
-  char *data;
-  uint64 key;
-  uint64 mapping;
-  ubyte ready;
-  ubyte num;
-  ubyte symmetric;
-  ubyte has_pawns;
-  ubyte pawns[2];
-  struct {
-    struct PairsData *precomp;
-    int factor[TBPIECES];
-    ubyte pieces[TBPIECES];
-    ubyte norm[TBPIECES];
-  } file[4];
-  ubyte flags[4];
-  ushort map_idx[4][4];
-  ubyte *map;
-};
-
-struct TBHashEntry {
-  uint64 key;
-  struct TBEntry *ptr;
-};
-
-struct DTZTableEntry {
-  uint64 key1;
-  uint64 key2;
-  struct TBEntry *entry;
-};
-
-#endif
-

src/syzygy/tbprobe.h

@@ -1,18 +1,78 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (c) 2013 Ronald de Man
+  Copyright (C) 2016-2018 Marco Costalba, Lucas Braesch
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
 #ifndef TBPROBE_H
 #define TBPROBE_H
 
+#include <ostream>
+
 #include "../search.h"
 
 namespace Tablebases {
 
+enum WDLScore {
+    WDLLoss        = -2, // Loss
+    WDLBlessedLoss = -1, // Loss, but draw under 50-move rule
+    WDLDraw        =  0, // Draw
+    WDLCursedWin   =  1, // Win, but draw under 50-move rule
+    WDLWin         =  2, // Win
+
+    WDLScoreNone  = -1000
+};
+
+// Possible states after a probing operation
+enum ProbeState {
+    FAIL              =  0, // Probe failed (missing file table)
+    OK                =  1, // Probe succesful
+    CHANGE_STM        = -1, // DTZ should check the other side
+    ZEROING_BEST_MOVE =  2  // Best move zeroes DTZ (capture or pawn move)
+};
+
 extern int MaxCardinality;
 
-void init(const std::string& path);
-int probe_wdl(Position& pos, int *success);
-int probe_dtz(Position& pos, int *success);
-bool root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score);
-bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score);
-void filter_root_moves(Position& pos, Search::RootMoves& rootMoves);
+void init(const std::string& paths);
+WDLScore probe_wdl(Position& pos, ProbeState* result);
+int probe_dtz(Position& pos, ProbeState* result);
+bool root_probe(Position& pos, Search::RootMoves& rootMoves);
+bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves);
+void rank_root_moves(Position& pos, Search::RootMoves& rootMoves);
+
+inline std::ostream& operator<<(std::ostream& os, const WDLScore v) {
+
+    os << (v == WDLLoss        ? "Loss" :
+           v == WDLBlessedLoss ? "Blessed loss" :
+           v == WDLDraw        ? "Draw" :
+           v == WDLCursedWin   ? "Cursed win" :
+           v == WDLWin         ? "Win" : "None");
+
+    return os;
+}
+
+inline std::ostream& operator<<(std::ostream& os, const ProbeState v) {
+
+    os << (v == FAIL              ? "Failed" :
+           v == OK                ? "Success" :
+           v == CHANGE_STM        ? "Probed opponent side" :
+           v == ZEROING_BEST_MOVE ? "Best move zeroes DTZ" : "None");
+
+    return os;
+}
 
 }
 

src/thread.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,178 +26,154 @@
 #include "thread.h"
 #include "uci.h"
 #include "syzygy/tbprobe.h"
+#include "tt.h"
 
 ThreadPool Threads; // Global object
 
-/// Thread constructor launches the thread and then waits until it goes to sleep
-/// in idle_loop().
 
-Thread::Thread() {
+/// Thread constructor launches the thread and waits until it goes to sleep
+/// in idle_loop(). Note that 'searching' and 'exit' should be alredy set.
 
-  resetCalls = exit = false;
-  maxPly = callsCnt = 0;
-  tbHits = 0;
-  history.clear();
-  counterMoves.clear();
-  idx = Threads.size(); // Start from 0
+Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) {
 
-  std::unique_lock<Mutex> lk(mutex);
-  searching = true;
-  nativeThread = std::thread(&Thread::idle_loop, this);
-  sleepCondition.wait(lk, [&]{ return !searching; });
+  wait_for_search_finished();
 }
 
 
-/// Thread destructor waits for thread termination before returning
+/// Thread destructor wakes up the thread in idle_loop() and waits
+/// for its termination. Thread should be already waiting.
 
 Thread::~Thread() {
 
-  mutex.lock();
+  assert(!searching);
+
   exit = true;
-  sleepCondition.notify_one();
-  mutex.unlock();
-  nativeThread.join();
+  start_searching();
+  stdThread.join();
 }
 
 
-/// Thread::wait_for_search_finished() waits on sleep condition
-/// until not searching
+/// Thread::clear() reset histories, usually before a new game
+
+void Thread::clear() {
+
+  counterMoves.fill(MOVE_NONE);
+  mainHistory.fill(0);
+  captureHistory.fill(0);
+
+  for (auto& to : continuationHistory)
+      for (auto& h : to)
+          h->fill(0);
+
+  continuationHistory[NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
+}
+
+/// Thread::start_searching() wakes up the thread that will start the search
+
+void Thread::start_searching() {
+
+  std::lock_guard<Mutex> lk(mutex);
+  searching = true;
+  cv.notify_one(); // Wake up the thread in idle_loop()
+}
+
+
+/// Thread::wait_for_search_finished() blocks on the condition variable
+/// until the thread has finished searching.
 
 void Thread::wait_for_search_finished() {
 
   std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return !searching; });
+  cv.wait(lk, [&]{ return !searching; });
 }
 
 
-/// Thread::wait() waits on sleep condition until condition is true
-
-void Thread::wait(std::atomic_bool& condition) {
-
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return bool(condition); });
-}
-
-
-/// Thread::start_searching() wakes up the thread that will start the search
-
-void Thread::start_searching(bool resume) {
-
-  std::unique_lock<Mutex> lk(mutex);
-
-  if (!resume)
-      searching = true;
-
-  sleepCondition.notify_one();
-}
-
-
-/// Thread::idle_loop() is where the thread is parked when it has no work to do
+/// Thread::idle_loop() is where the thread is parked, blocked on the
+/// condition variable, when it has no work to do.
 
 void Thread::idle_loop() {
 
-  while (!exit)
+  // If OS already scheduled us on a different group than 0 then don't overwrite
+  // the choice, eventually we are one of many one-threaded processes running on
+  // some Windows NUMA hardware, for instance in fishtest. To make it simple,
+  // just check if running threads are below a threshold, in this case all this
+  // NUMA machinery is not needed.
+  if (Options["Threads"] > 8)
+      WinProcGroup::bindThisThread(idx);
+
+  while (true)
   {
       std::unique_lock<Mutex> lk(mutex);
-
       searching = false;
+      cv.notify_one(); // Wake up anyone waiting for search finished
+      cv.wait(lk, [&]{ return searching; });
 
-      while (!searching && !exit)
-      {
-          sleepCondition.notify_one(); // Wake up any waiting thread
-          sleepCondition.wait(lk);
-      }
+      if (exit)
+          return;
 
       lk.unlock();
 
-      if (!exit)
-          search();
+      search();
   }
 }
 
+/// ThreadPool::set() creates/destroys threads to match the requested number.
+/// Created and launched threads will go immediately to sleep in idle_loop.
+/// Upon resizing, threads are recreated to allow for binding if necessary.
 
-/// ThreadPool::init() creates and launches requested threads that will go
-/// immediately to sleep. We cannot use a constructor because Threads is a
-/// static object and we need a fully initialized engine at this point due to
-/// allocation of Endgames in the Thread constructor.
+void ThreadPool::set(size_t requested) {
 
-void ThreadPool::init() {
+  if (size() > 0) { // destroy any existing thread(s)
+      main()->wait_for_search_finished();
 
-  push_back(new MainThread);
-  read_uci_options();
+      while (size() > 0)
+          delete back(), pop_back();
+  }
+
+  if (requested > 0) { // create new thread(s)
+      push_back(new MainThread(0));
+
+      while (size() < requested)
+          push_back(new Thread(size()));
+      clear();
+  }
+
+  // Reallocate the hash with the new threadpool size
+  TT.resize(Options["Hash"]);
 }
 
+/// ThreadPool::clear() sets threadPool data to initial values.
 
-/// ThreadPool::exit() terminates threads before the program exits. Cannot be
-/// done in destructor because threads must be terminated before deleting any
-/// static objects while still in main().
+void ThreadPool::clear() {
 
-void ThreadPool::exit() {
-
-  while (size())
-      delete back(), pop_back();
-}
-
-
-/// ThreadPool::read_uci_options() updates internal threads parameters from the
-/// corresponding UCI options and creates/destroys threads to match requested
-/// number. Thread objects are dynamically allocated.
-
-void ThreadPool::read_uci_options() {
-
-  size_t requested = Options["Threads"];
-
-  assert(requested > 0);
-
-  while (size() < requested)
-      push_back(new Thread);
-
-  while (size() > requested)
-      delete back(), pop_back();
-}
-
-
-/// ThreadPool::nodes_searched() returns the number of nodes searched
-
-uint64_t ThreadPool::nodes_searched() const {
-
-  uint64_t nodes = 0;
   for (Thread* th : *this)
-      nodes += th->rootPos.nodes_searched();
-  return nodes;
+      th->clear();
+
+  main()->callsCnt = 0;
+  main()->previousScore = VALUE_INFINITE;
+  main()->previousTimeReduction = 1.0;
 }
 
-
-/// ThreadPool::tb_hits() returns the number of TB hits
-
-uint64_t ThreadPool::tb_hits() const {
-
-  uint64_t hits = 0;
-  for (Thread* th : *this)
-      hits += th->tbHits;
-  return hits;
-}
-
-
-/// ThreadPool::start_thinking() wakes up the main thread sleeping in idle_loop()
-/// and starts a new search, then returns immediately.
+/// ThreadPool::start_thinking() wakes up main thread waiting in idle_loop() and
+/// returns immediately. Main thread will wake up other threads and start the search.
 
 void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
-                                const Search::LimitsType& limits) {
+                                const Search::LimitsType& limits, bool ponderMode) {
 
   main()->wait_for_search_finished();
 
-  Search::Signals.stopOnPonderhit = Search::Signals.stop = false;
+  stopOnPonderhit = stop = false;
+  ponder = ponderMode;
   Search::Limits = limits;
   Search::RootMoves rootMoves;
 
   for (const auto& m : MoveList<LEGAL>(pos))
       if (   limits.searchmoves.empty()
           || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
-          rootMoves.push_back(Search::RootMove(m));
+          rootMoves.emplace_back(m);
 
   if (!rootMoves.empty())
-      Tablebases::filter_root_moves(pos, rootMoves);
+      Tablebases::rank_root_moves(pos, rootMoves);
 
   // After ownership transfer 'states' becomes empty, so if we stop the search
   // and call 'go' again without setting a new position states.get() == NULL.
@@ -206,18 +182,22 @@ void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
   if (states.get())
       setupStates = std::move(states); // Ownership transfer, states is now empty
 
+  // We use Position::set() to set root position across threads. But there are
+  // some StateInfo fields (previous, pliesFromNull, capturedPiece) that cannot
+  // be deduced from a fen string, so set() clears them and to not lose the info
+  // we need to backup and later restore setupStates->back(). Note that setupStates
+  // is shared by threads but is accessed in read-only mode.
   StateInfo tmp = setupStates->back();
 
-  for (Thread* th : Threads)
+  for (Thread* th : *this)
   {
-      th->maxPly = 0;
-      th->tbHits = 0;
-      th->rootDepth = DEPTH_ZERO;
+      th->nodes = th->tbHits = th->nmpMinPly = 0;
+      th->rootDepth = th->completedDepth = DEPTH_ZERO;
       th->rootMoves = rootMoves;
       th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
   }
 
-  setupStates->back() = tmp; // Restore st->previous, cleared by Position::set()
+  setupStates->back() = tmp;
 
   main()->start_searching();
 }

src/thread.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -22,7 +22,6 @@
 #define THREAD_H_INCLUDED
 
 #include <atomic>
-#include <bitset>
 #include <condition_variable>
 #include <mutex>
 #include <thread>
@@ -36,74 +35,88 @@
 #include "thread_win32.h"
 
 
-/// Thread struct keeps together all the thread-related stuff. We also use
-/// per-thread pawn and material hash tables so that once we get a pointer to an
-/// entry its life time is unlimited and we don't have to care about someone
-/// changing the entry under our feet.
+/// Thread class keeps together all the thread-related stuff. We use
+/// per-thread pawn and material hash tables so that once we get a
+/// pointer to an entry its life time is unlimited and we don't have
+/// to care about someone changing the entry under our feet.
 
 class Thread {
 
-  std::thread nativeThread;
   Mutex mutex;
-  ConditionVariable sleepCondition;
-  bool exit, searching;
+  ConditionVariable cv;
+  size_t idx;
+  bool exit = false, searching = true; // Set before starting std::thread
+  std::thread stdThread;
 
 public:
-  Thread();
+  explicit Thread(size_t);
   virtual ~Thread();
   virtual void search();
+  void clear();
   void idle_loop();
-  void start_searching(bool resume = false);
+  void start_searching();
   void wait_for_search_finished();
-  void wait(std::atomic_bool& b);
 
   Pawns::Table pawnsTable;
   Material::Table materialTable;
   Endgames endgames;
-  size_t idx, PVIdx;
-  int maxPly, callsCnt;
-  uint64_t tbHits;
+  size_t pvIdx, pvLast;
+  int selDepth, nmpMinPly;
+  Color nmpColor;
+  std::atomic<uint64_t> nodes, tbHits;
 
   Position rootPos;
   Search::RootMoves rootMoves;
-  Depth rootDepth;
-  Depth completedDepth;
-  std::atomic_bool resetCalls;
-  HistoryStats history;
-  MoveStats counterMoves;
-  FromToStats fromTo;
-  CounterMoveHistoryStats counterMoveHistory;
+  Depth rootDepth, completedDepth;
+  CounterMoveHistory counterMoves;
+  ButterflyHistory mainHistory;
+  CapturePieceToHistory captureHistory;
+  ContinuationHistory continuationHistory;
+  Score contempt;
 };
 
 
-/// MainThread is a derived class with a specific overload for the main thread
+/// MainThread is a derived class specific for main thread
 
 struct MainThread : public Thread {
-  virtual void search();
 
-  bool easyMovePlayed, failedLow;
-  double bestMoveChanges;
+  using Thread::Thread;
+
+  void search() override;
+  void check_time();
+
+  double bestMoveChanges, previousTimeReduction;
   Value previousScore;
+  int callsCnt;
 };
 
 
 /// ThreadPool struct handles all the threads-related stuff like init, starting,
 /// parking and, most importantly, launching a thread. All the access to threads
-/// data is done through this class.
+/// is done through this class.
 
 struct ThreadPool : public std::vector<Thread*> {
 
-  void init(); // No constructor and destructor, threads rely on globals that should
-  void exit(); // be initialized and valid during the whole thread lifetime.
+  void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
+  void clear();
+  void set(size_t);
 
-  MainThread* main() { return static_cast<MainThread*>(at(0)); }
-  void start_thinking(Position&, StateListPtr&, const Search::LimitsType&);
-  void read_uci_options();
-  uint64_t nodes_searched() const;
-  uint64_t tb_hits() const;
+  MainThread* main()        const { return static_cast<MainThread*>(front()); }
+  uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
+  uint64_t tb_hits()        const { return accumulate(&Thread::tbHits); }
+
+  std::atomic_bool stop, ponder, stopOnPonderhit;
 
 private:
   StateListPtr setupStates;
+
+  uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {
+
+    uint64_t sum = 0;
+    for (Thread* th : *this)
+        sum += (th->*member).load(std::memory_order_relaxed);
+    return sum;
+  }
 };
 
 extern ThreadPool Threads;

src/thread_win32.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by

src/timeman.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -32,9 +32,9 @@ namespace {
 
   enum TimeType { OptimumTime, MaxTime };
 
-  const int MoveHorizon   = 50;   // Plan time management at most this many moves ahead
-  const double MaxRatio   = 7.09; // When in trouble, we can step over reserved time with this ratio
-  const double StealRatio = 0.35; // However we must not steal time from remaining moves over this ratio
+  constexpr int MoveHorizon   = 50;   // Plan time management at most this many moves ahead
+  constexpr double MaxRatio   = 7.3;  // When in trouble, we can step over reserved time with this ratio
+  constexpr double StealRatio = 0.34; // However we must not steal time from remaining moves over this ratio
 
 
   // move_importance() is a skew-logistic function based on naive statistical
@@ -44,21 +44,21 @@ namespace {
 
   double move_importance(int ply) {
 
-    const double XScale = 7.64;
-    const double XShift = 58.4;
-    const double Skew   = 0.183;
+    constexpr double XScale = 6.85;
+    constexpr double XShift = 64.5;
+    constexpr double Skew   = 0.171;
 
     return pow((1 + exp((ply - XShift) / XScale)), -Skew) + DBL_MIN; // Ensure non-zero
   }
 
   template<TimeType T>
-  int remaining(int myTime, int movesToGo, int ply, int slowMover) {
+  TimePoint remaining(TimePoint myTime, int movesToGo, int ply, TimePoint slowMover) {
 
-    const double TMaxRatio   = (T == OptimumTime ? 1 : MaxRatio);
-    const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
+    constexpr double TMaxRatio   = (T == OptimumTime ? 1.0 : MaxRatio);
+    constexpr double TStealRatio = (T == OptimumTime ? 0.0 : StealRatio);
 
-    double moveImportance = (move_importance(ply) * slowMover) / 100;
-    double otherMovesImportance = 0;
+    double moveImportance = (move_importance(ply) * slowMover) / 100.0;
+    double otherMovesImportance = 0.0;
 
     for (int i = 1; i < movesToGo; ++i)
         otherMovesImportance += move_importance(ply + 2 * i);
@@ -66,7 +66,7 @@ namespace {
     double ratio1 = (TMaxRatio * moveImportance) / (TMaxRatio * moveImportance + otherMovesImportance);
     double ratio2 = (moveImportance + TStealRatio * otherMovesImportance) / (moveImportance + otherMovesImportance);
 
-    return int(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast
+    return TimePoint(myTime * std::min(ratio1, ratio2)); // Intel C++ asks for an explicit cast
   }
 
 } // namespace
@@ -83,22 +83,23 @@ namespace {
 
 void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
 
-  int minThinkingTime = Options["Minimum Thinking Time"];
-  int moveOverhead    = Options["Move Overhead"];
-  int slowMover       = Options["Slow Mover"];
-  int npmsec          = Options["nodestime"];
+  TimePoint minThinkingTime = Options["Minimum Thinking Time"];
+  TimePoint moveOverhead    = Options["Move Overhead"];
+  TimePoint slowMover       = Options["Slow Mover"];
+  TimePoint npmsec          = Options["nodestime"];
+  TimePoint hypMyTime;
 
   // If we have to play in 'nodes as time' mode, then convert from time
   // to nodes, and use resulting values in time management formulas.
-  // WARNING: Given npms (nodes per millisecond) must be much lower then
-  // the real engine speed to avoid time losses.
+  // WARNING: to avoid time losses, the given npmsec (nodes per millisecond)
+  // must be much lower than the real engine speed.
   if (npmsec)
   {
       if (!availableNodes) // Only once at game start
           availableNodes = npmsec * limits.time[us]; // Time is in msec
 
-      // Convert from millisecs to nodes
-      limits.time[us] = (int)availableNodes;
+      // Convert from milliseconds to nodes
+      limits.time[us] = TimePoint(availableNodes);
       limits.inc[us] *= npmsec;
       limits.npmsec = npmsec;
   }
@@ -106,22 +107,22 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
   startTime = limits.startTime;
   optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime);
 
-  const int MaxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
+  const int maxMTG = limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon;
 
-  // We calculate optimum time usage for different hypothetical "moves to go"-values
+  // We calculate optimum time usage for different hypothetical "moves to go" values
   // and choose the minimum of calculated search time values. Usually the greatest
   // hypMTG gives the minimum values.
-  for (int hypMTG = 1; hypMTG <= MaxMTG; ++hypMTG)
+  for (int hypMTG = 1; hypMTG <= maxMTG; ++hypMTG)
   {
       // Calculate thinking time for hypothetical "moves to go"-value
-      int hypMyTime =  limits.time[us]
-                     + limits.inc[us] * (hypMTG - 1)
-                     - moveOverhead * (2 + std::min(hypMTG, 40));
+      hypMyTime =  limits.time[us]
+                 + limits.inc[us] * (hypMTG - 1)
+                 - moveOverhead * (2 + std::min(hypMTG, 40));
 
-      hypMyTime = std::max(hypMyTime, 0);
+      hypMyTime = std::max(hypMyTime, TimePoint(0));
 
-      int t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
-      int t2 = minThinkingTime + remaining<MaxTime    >(hypMyTime, hypMTG, ply, slowMover);
+      TimePoint t1 = minThinkingTime + remaining<OptimumTime>(hypMyTime, hypMTG, ply, slowMover);
+      TimePoint t2 = minThinkingTime + remaining<MaxTime    >(hypMyTime, hypMTG, ply, slowMover);
 
       optimumTime = std::min(t1, optimumTime);
       maximumTime = std::min(t2, maximumTime);

src/timeman.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,16 +31,17 @@
 class TimeManagement {
 public:
   void init(Search::LimitsType& limits, Color us, int ply);
-  int optimum() const { return optimumTime; }
-  int maximum() const { return maximumTime; }
-  int elapsed() const { return int(Search::Limits.npmsec ? Threads.nodes_searched() : now() - startTime); }
+  TimePoint optimum() const { return optimumTime; }
+  TimePoint maximum() const { return maximumTime; }
+  TimePoint elapsed() const { return Search::Limits.npmsec ?
+                                     TimePoint(Threads.nodes_searched()) : now() - startTime; }
 
   int64_t availableNodes; // When in 'nodes as time' mode
 
 private:
   TimePoint startTime;
-  int optimumTime;
-  int maximumTime;
+  TimePoint optimumTime;
+  TimePoint maximumTime;
 };
 
 extern TimeManagement Time;

src/tt.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,12 +20,37 @@
 
 #include <cstring>   // For std::memset
 #include <iostream>
+#include <thread>
 
 #include "bitboard.h"
+#include "misc.h"
 #include "tt.h"
+#include "uci.h"
 
 TranspositionTable TT; // Our global transposition table
 
+/// TTEntry::save saves a TTEntry
+void TTEntry::save(Key k, Value v, Bound b, Depth d, Move m, Value ev) {
+
+  assert(d / ONE_PLY * ONE_PLY == d);
+
+  // Preserve any existing move for the same position
+  if (m || (k >> 48) != key16)
+      move16 = (uint16_t)m;
+
+  // Overwrite less valuable entries
+  if (  (k >> 48) != key16
+      || d / ONE_PLY > depth8 - 4
+      || b == BOUND_EXACT)
+  {
+      key16     = (uint16_t)(k >> 48);
+      value16   = (int16_t)v;
+      eval16    = (int16_t)ev;
+      genBound8 = (uint8_t)(TT.generation8 | b);
+      depth8    = (int8_t)(d / ONE_PLY);
+  }
+}
+
 
 /// TranspositionTable::resize() sets the size of the transposition table,
 /// measured in megabytes. Transposition table consists of a power of 2 number
@@ -33,15 +58,10 @@ TranspositionTable TT; // Our global transposition table
 
 void TranspositionTable::resize(size_t mbSize) {
 
-  size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
-
-  if (newClusterCount == clusterCount)
-      return;
-
-  clusterCount = newClusterCount;
+  clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
 
   free(mem);
-  mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
+  mem = malloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1);
 
   if (!mem)
   {
@@ -51,18 +71,38 @@ void TranspositionTable::resize(size_t mbSize) {
   }
 
   table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
+  clear();
 }
 
 
-/// TranspositionTable::clear() overwrites the entire transposition table
-/// with zeros. It is called whenever the table is resized, or when the
-/// user asks the program to clear the table (from the UCI interface).
+/// TranspositionTable::clear() initializes the entire transposition table to zero,
+//  in a multi-threaded way.
 
 void TranspositionTable::clear() {
 
-  std::memset(table, 0, clusterCount * sizeof(Cluster));
-}
+  std::vector<std::thread> threads;
 
+  for (size_t idx = 0; idx < Options["Threads"]; idx++)
+  {
+      threads.emplace_back([this, idx]() {
+
+          // Thread binding gives faster search on systems with a first-touch policy
+          if (Options["Threads"] > 8)
+              WinProcGroup::bindThisThread(idx);
+
+          // Each thread will zero its part of the hash table
+          const size_t stride = clusterCount / Options["Threads"],
+                       start  = stride * idx,
+                       len    = idx != Options["Threads"] - 1 ?
+                                stride : clusterCount - start;
+
+          std::memset(&table[start], 0, len * sizeof(Cluster));
+      });
+  }
+
+  for (std::thread& th: threads)
+      th.join();
+}
 
 /// TranspositionTable::probe() looks up the current position in the transposition
 /// table. It returns true and a pointer to the TTEntry if the position is found.
@@ -79,8 +119,7 @@ TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
   for (int i = 0; i < ClusterSize; ++i)
       if (!tte[i].key16 || tte[i].key16 == key16)
       {
-          if ((tte[i].genBound8 & 0xFC) != generation8 && tte[i].key16)
-              tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
+          tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
 
           return found = (bool)tte[i].key16, &tte[i];
       }

src/tt.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -41,28 +41,7 @@ struct TTEntry {
   Value eval()  const { return (Value)eval16; }
   Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)); }
   Bound bound() const { return (Bound)(genBound8 & 0x3); }
-
-  void save(Key k, Value v, Bound b, Depth d, Move m, Value ev, uint8_t g) {
-
-    assert(d / ONE_PLY * ONE_PLY == d);
-
-    // Preserve any existing move for the same position
-    if (m || (k >> 48) != key16)
-        move16 = (uint16_t)m;
-
-    // Don't overwrite more valuable entries
-    if (  (k >> 48) != key16
-        || d / ONE_PLY > depth8 - 4
-     /* || g != (genBound8 & 0xFC) // Matching non-zero keys are already refreshed by probe() */
-        || b == BOUND_EXACT)
-    {
-        key16     = (uint16_t)(k >> 48);
-        value16   = (int16_t)v;
-        eval16    = (int16_t)ev;
-        genBound8 = (uint8_t)(g | b);
-        depth8    = (int8_t)(d / ONE_PLY);
-    }
-  }
+  void save(Key k, Value v, Bound b, Depth d, Move m, Value ev);
 
 private:
   friend class TranspositionTable;
@@ -85,8 +64,8 @@ private:
 
 class TranspositionTable {
 
-  static const int CacheLineSize = 64;
-  static const int ClusterSize = 3;
+  static constexpr int CacheLineSize = 64;
+  static constexpr int ClusterSize = 3;
 
   struct Cluster {
     TTEntry entry[ClusterSize];
@@ -98,18 +77,19 @@ class TranspositionTable {
 public:
  ~TranspositionTable() { free(mem); }
   void new_search() { generation8 += 4; } // Lower 2 bits are used by Bound
-  uint8_t generation() const { return generation8; }
   TTEntry* probe(const Key key, bool& found) const;
   int hashfull() const;
   void resize(size_t mbSize);
   void clear();
 
-  // The lowest order bits of the key are used to get the index of the cluster
+  // The 32 lowest order bits of the key are used to get the index of the cluster
   TTEntry* first_entry(const Key key) const {
-    return &table[(size_t)key & (clusterCount - 1)].entry[0];
+    return &table[(uint32_t(key) * uint64_t(clusterCount)) >> 32].entry[0];
   }
 
 private:
+  friend struct TTEntry;
+
   size_t clusterCount;
   Cluster* table;
   void* mem;

src/types.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -76,32 +76,32 @@
 #  include <immintrin.h> // Header for _pext_u64() intrinsic
 #  define pext(b, m) _pext_u64(b, m)
 #else
-#  define pext(b, m) (0)
+#  define pext(b, m) 0
 #endif
 
 #ifdef USE_POPCNT
-const bool HasPopCnt = true;
+constexpr bool HasPopCnt = true;
 #else
-const bool HasPopCnt = false;
+constexpr bool HasPopCnt = false;
 #endif
 
 #ifdef USE_PEXT
-const bool HasPext = true;
+constexpr bool HasPext = true;
 #else
-const bool HasPext = false;
+constexpr bool HasPext = false;
 #endif
 
 #ifdef IS_64BIT
-const bool Is64Bit = true;
+constexpr bool Is64Bit = true;
 #else
-const bool Is64Bit = false;
+constexpr bool Is64Bit = false;
 #endif
 
 typedef uint64_t Key;
 typedef uint64_t Bitboard;
 
-const int MAX_MOVES = 256;
-const int MAX_PLY   = 128;
+constexpr int MAX_MOVES = 256;
+constexpr int MAX_PLY   = 128;
 
 /// A move needs 16 bits to be stored
 ///
@@ -128,7 +128,7 @@ enum MoveType {
 };
 
 enum Color {
-  WHITE, BLACK, NO_COLOR, COLOR_NB = 2
+  WHITE, BLACK, COLOR_NB = 2
 };
 
 enum CastlingSide {
@@ -145,12 +145,6 @@ enum CastlingRight {
   CASTLING_RIGHT_NB = 16
 };
 
-template<Color C, CastlingSide S> struct MakeCastling {
-  static const CastlingRight
-  right = C == WHITE ? S == QUEEN_SIDE ? WHITE_OOO : WHITE_OO
-                     : S == QUEEN_SIDE ? BLACK_OOO : BLACK_OO;
-};
-
 enum Phase {
   PHASE_ENDGAME,
   PHASE_MIDGAME = 128,
@@ -159,7 +153,6 @@ enum Phase {
 
 enum ScaleFactor {
   SCALE_FACTOR_DRAW    = 0,
-  SCALE_FACTOR_ONEPAWN = 48,
   SCALE_FACTOR_NORMAL  = 64,
   SCALE_FACTOR_MAX     = 128,
   SCALE_FACTOR_NONE    = 255
@@ -183,11 +176,11 @@ enum Value : int {
   VALUE_MATE_IN_MAX_PLY  =  VALUE_MATE - 2 * MAX_PLY,
   VALUE_MATED_IN_MAX_PLY = -VALUE_MATE + 2 * MAX_PLY,
 
-  PawnValueMg   = 188,   PawnValueEg   = 248,
-  KnightValueMg = 753,   KnightValueEg = 832,
-  BishopValueMg = 826,   BishopValueEg = 897,
-  RookValueMg   = 1285,  RookValueEg   = 1371,
-  QueenValueMg  = 2513,  QueenValueEg  = 2650,
+  PawnValueMg   = 136,   PawnValueEg   = 208,
+  KnightValueMg = 782,   KnightValueEg = 865,
+  BishopValueMg = 830,   BishopValueEg = 918,
+  RookValueMg   = 1289,  RookValueEg   = 1378,
+  QueenValueMg  = 2529,  QueenValueEg  = 2687,
 
   MidgameLimit  = 15258, EndgameLimit  = 3915
 };
@@ -205,11 +198,9 @@ enum Piece {
   PIECE_NB = 16
 };
 
-const Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
-                         B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING };
 extern Value PieceValue[PHASE_NB][PIECE_NB];
 
-enum Depth {
+enum Depth : int {
 
   ONE_PLY = 1,
 
@@ -224,7 +215,7 @@ enum Depth {
 
 static_assert(!(ONE_PLY & (ONE_PLY - 1)), "ONE_PLY is not a power of 2");
 
-enum Square {
+enum Square : int {
   SQ_A1, SQ_B1, SQ_C1, SQ_D1, SQ_E1, SQ_F1, SQ_G1, SQ_H1,
   SQ_A2, SQ_B2, SQ_C2, SQ_D2, SQ_E2, SQ_F2, SQ_G2, SQ_H2,
   SQ_A3, SQ_B3, SQ_C3, SQ_D3, SQ_E3, SQ_F3, SQ_G3, SQ_H3,
@@ -235,12 +226,14 @@ enum Square {
   SQ_A8, SQ_B8, SQ_C8, SQ_D8, SQ_E8, SQ_F8, SQ_G8, SQ_H8,
   SQ_NONE,
 
-  SQUARE_NB = 64,
+  SQUARE_NB = 64
+};
 
+enum Direction : int {
   NORTH =  8,
   EAST  =  1,
-  SOUTH = -8,
-  WEST  = -1,
+  SOUTH = -NORTH,
+  WEST  = -EAST,
 
   NORTH_EAST = NORTH + EAST,
   SOUTH_EAST = SOUTH + EAST,
@@ -257,13 +250,13 @@ enum Rank : int {
 };
 
 
-/// Score enum stores a middlegame and an endgame value in a single integer
-/// (enum). The least significant 16 bits are used to store the endgame value
-/// and the upper 16 bits are used to store the middlegame value. Take some
-/// care to avoid left-shifting a signed int to avoid undefined behavior.
+/// Score enum stores a middlegame and an endgame value in a single integer (enum).
+/// The least significant 16 bits are used to store the middlegame value and the
+/// upper 16 bits are used to store the endgame value. We have to take care to
+/// avoid left-shifting a signed int to avoid undefined behavior.
 enum Score : int { SCORE_ZERO };
 
-inline Score make_score(int mg, int eg) {
+constexpr Score make_score(int mg, int eg) {
   return Score((int)((unsigned int)eg << 16) + mg);
 }
 
@@ -271,97 +264,123 @@ inline Score make_score(int mg, int eg) {
 /// according to the standard a simple cast to short is implementation defined
 /// and so is a right shift of a signed integer.
 inline Value eg_value(Score s) {
-
   union { uint16_t u; int16_t s; } eg = { uint16_t(unsigned(s + 0x8000) >> 16) };
   return Value(eg.s);
 }
 
 inline Value mg_value(Score s) {
-
   union { uint16_t u; int16_t s; } mg = { uint16_t(unsigned(s)) };
   return Value(mg.s);
 }
 
-#define ENABLE_BASE_OPERATORS_ON(T)                             \
-inline T operator+(T d1, T d2) { return T(int(d1) + int(d2)); } \
-inline T operator-(T d1, T d2) { return T(int(d1) - int(d2)); } \
-inline T operator*(int i, T d) { return T(i * int(d)); }        \
-inline T operator*(T d, int i) { return T(int(d) * i); }        \
-inline T operator-(T d) { return T(-int(d)); }                  \
-inline T& operator+=(T& d1, T d2) { return d1 = d1 + d2; }      \
-inline T& operator-=(T& d1, T d2) { return d1 = d1 - d2; }      \
-inline T& operator*=(T& d, int i) { return d = T(int(d) * i); }
+#define ENABLE_BASE_OPERATORS_ON(T)                                \
+constexpr T operator+(T d1, T d2) { return T(int(d1) + int(d2)); } \
+constexpr T operator-(T d1, T d2) { return T(int(d1) - int(d2)); } \
+constexpr T operator-(T d) { return T(-int(d)); }                  \
+inline T& operator+=(T& d1, T d2) { return d1 = d1 + d2; }         \
+inline T& operator-=(T& d1, T d2) { return d1 = d1 - d2; }
 
-#define ENABLE_FULL_OPERATORS_ON(T)                             \
-ENABLE_BASE_OPERATORS_ON(T)                                     \
-inline T& operator++(T& d) { return d = T(int(d) + 1); }        \
-inline T& operator--(T& d) { return d = T(int(d) - 1); }        \
-inline T operator/(T d, int i) { return T(int(d) / i); }        \
-inline int operator/(T d1, T d2) { return int(d1) / int(d2); }  \
+#define ENABLE_INCR_OPERATORS_ON(T)                                \
+inline T& operator++(T& d) { return d = T(int(d) + 1); }           \
+inline T& operator--(T& d) { return d = T(int(d) - 1); }
+
+#define ENABLE_FULL_OPERATORS_ON(T)                                \
+ENABLE_BASE_OPERATORS_ON(T)                                        \
+ENABLE_INCR_OPERATORS_ON(T)                                        \
+constexpr T operator*(int i, T d) { return T(i * int(d)); }        \
+constexpr T operator*(T d, int i) { return T(int(d) * i); }        \
+constexpr T operator/(T d, int i) { return T(int(d) / i); }        \
+constexpr int operator/(T d1, T d2) { return int(d1) / int(d2); }  \
+inline T& operator*=(T& d, int i) { return d = T(int(d) * i); }    \
 inline T& operator/=(T& d, int i) { return d = T(int(d) / i); }
 
 ENABLE_FULL_OPERATORS_ON(Value)
-ENABLE_FULL_OPERATORS_ON(PieceType)
-ENABLE_FULL_OPERATORS_ON(Piece)
-ENABLE_FULL_OPERATORS_ON(Color)
 ENABLE_FULL_OPERATORS_ON(Depth)
-ENABLE_FULL_OPERATORS_ON(Square)
-ENABLE_FULL_OPERATORS_ON(File)
-ENABLE_FULL_OPERATORS_ON(Rank)
+ENABLE_FULL_OPERATORS_ON(Direction)
+
+ENABLE_INCR_OPERATORS_ON(PieceType)
+ENABLE_INCR_OPERATORS_ON(Piece)
+ENABLE_INCR_OPERATORS_ON(Color)
+ENABLE_INCR_OPERATORS_ON(Square)
+ENABLE_INCR_OPERATORS_ON(File)
+ENABLE_INCR_OPERATORS_ON(Rank)
 
 ENABLE_BASE_OPERATORS_ON(Score)
 
 #undef ENABLE_FULL_OPERATORS_ON
+#undef ENABLE_INCR_OPERATORS_ON
 #undef ENABLE_BASE_OPERATORS_ON
 
 /// Additional operators to add integers to a Value
-inline Value operator+(Value v, int i) { return Value(int(v) + i); }
-inline Value operator-(Value v, int i) { return Value(int(v) - i); }
+constexpr Value operator+(Value v, int i) { return Value(int(v) + i); }
+constexpr Value operator-(Value v, int i) { return Value(int(v) - i); }
 inline Value& operator+=(Value& v, int i) { return v = v + i; }
 inline Value& operator-=(Value& v, int i) { return v = v - i; }
 
+/// Additional operators to add a Direction to a Square
+constexpr Square operator+(Square s, Direction d) { return Square(int(s) + int(d)); }
+constexpr Square operator-(Square s, Direction d) { return Square(int(s) - int(d)); }
+inline Square& operator+=(Square& s, Direction d) { return s = s + d; }
+inline Square& operator-=(Square& s, Direction d) { return s = s - d; }
+
 /// Only declared but not defined. We don't want to multiply two scores due to
 /// a very high risk of overflow. So user should explicitly convert to integer.
-inline Score operator*(Score s1, Score s2);
+Score operator*(Score, Score) = delete;
 
 /// Division of a Score must be handled separately for each term
 inline Score operator/(Score s, int i) {
   return make_score(mg_value(s) / i, eg_value(s) / i);
 }
 
-inline Color operator~(Color c) {
+/// Multiplication of a Score by an integer. We check for overflow in debug mode.
+inline Score operator*(Score s, int i) {
+
+  Score result = Score(int(s) * i);
+
+  assert(eg_value(result) == (i * eg_value(s)));
+  assert(mg_value(result) == (i * mg_value(s)));
+  assert((i == 0) || (result / i) == s);
+
+  return result;
+}
+
+constexpr Color operator~(Color c) {
   return Color(c ^ BLACK); // Toggle color
 }
 
-inline Square operator~(Square s) {
+constexpr Square operator~(Square s) {
   return Square(s ^ SQ_A8); // Vertical flip SQ_A1 -> SQ_A8
 }
 
-inline Piece operator~(Piece pc) {
+constexpr File operator~(File f) {
+  return File(f ^ FILE_H); // Horizontal flip FILE_A -> FILE_H
+}
+
+constexpr Piece operator~(Piece pc) {
   return Piece(pc ^ 8); // Swap color of piece B_KNIGHT -> W_KNIGHT
 }
 
-inline CastlingRight operator|(Color c, CastlingSide s) {
+constexpr CastlingRight operator|(Color c, CastlingSide s) {
   return CastlingRight(WHITE_OO << ((s == QUEEN_SIDE) + 2 * c));
 }
 
-inline Value mate_in(int ply) {
+constexpr Value mate_in(int ply) {
   return VALUE_MATE - ply;
 }
 
-inline Value mated_in(int ply) {
+constexpr Value mated_in(int ply) {
   return -VALUE_MATE + ply;
 }
 
-inline Square make_square(File f, Rank r) {
+constexpr Square make_square(File f, Rank r) {
   return Square((r << 3) + f);
 }
 
-inline Piece make_piece(Color c, PieceType pt) {
+constexpr Piece make_piece(Color c, PieceType pt) {
   return Piece((c << 3) + pt);
 }
 
-inline PieceType type_of(Piece pc) {
+constexpr PieceType type_of(Piece pc) {
   return PieceType(pc & 7);
 }
 
@@ -370,27 +389,27 @@ inline Color color_of(Piece pc) {
   return Color(pc >> 3);
 }
 
-inline bool is_ok(Square s) {
+constexpr bool is_ok(Square s) {
   return s >= SQ_A1 && s <= SQ_H8;
 }
 
-inline File file_of(Square s) {
+constexpr File file_of(Square s) {
   return File(s & 7);
 }
 
-inline Rank rank_of(Square s) {
+constexpr Rank rank_of(Square s) {
   return Rank(s >> 3);
 }
 
-inline Square relative_square(Color c, Square s) {
+constexpr Square relative_square(Color c, Square s) {
   return Square(s ^ (c * 56));
 }
 
-inline Rank relative_rank(Color c, Rank r) {
+constexpr Rank relative_rank(Color c, Rank r) {
   return Rank(r ^ (c * 7));
 }
 
-inline Rank relative_rank(Color c, Square s) {
+constexpr Rank relative_rank(Color c, Square s) {
   return relative_rank(c, rank_of(s));
 }
 
@@ -399,36 +418,40 @@ inline bool opposite_colors(Square s1, Square s2) {
   return ((s >> 3) ^ s) & 1;
 }
 
-inline Square pawn_push(Color c) {
+constexpr Direction pawn_push(Color c) {
   return c == WHITE ? NORTH : SOUTH;
 }
 
-inline Square from_sq(Move m) {
+constexpr Square from_sq(Move m) {
   return Square((m >> 6) & 0x3F);
 }
 
-inline Square to_sq(Move m) {
+constexpr Square to_sq(Move m) {
   return Square(m & 0x3F);
 }
 
-inline MoveType type_of(Move m) {
+constexpr int from_to(Move m) {
+ return m & 0xFFF;
+}
+
+constexpr MoveType type_of(Move m) {
   return MoveType(m & (3 << 14));
 }
 
-inline PieceType promotion_type(Move m) {
+constexpr PieceType promotion_type(Move m) {
   return PieceType(((m >> 12) & 3) + KNIGHT);
 }
 
-inline Move make_move(Square from, Square to) {
+constexpr Move make_move(Square from, Square to) {
   return Move((from << 6) + to);
 }
 
 template<MoveType T>
-inline Move make(Square from, Square to, PieceType pt = KNIGHT) {
+constexpr Move make(Square from, Square to, PieceType pt = KNIGHT) {
   return Move(T + ((pt - KNIGHT) << 12) + (from << 6) + to);
 }
 
-inline bool is_ok(Move m) {
+constexpr bool is_ok(Move m) {
   return from_sq(m) != to_sq(m); // Catch MOVE_NULL and MOVE_NONE
 }
 

src/uci.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -18,6 +18,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <cassert>
 #include <iostream>
 #include <sstream>
 #include <string>
@@ -28,29 +29,26 @@
 #include "search.h"
 #include "thread.h"
 #include "timeman.h"
+#include "tt.h"
 #include "uci.h"
+#include "syzygy/tbprobe.h"
 
 using namespace std;
 
-extern void benchmark(const Position& pos, istream& is);
+extern vector<string> setup_bench(const Position&, istream&);
 
 namespace {
 
   // FEN string of the initial position, normal chess
   const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
 
-  // A list to keep track of the position states along the setup moves (from the
-  // start position to the position just before the search starts). Needed by
-  // 'draw by repetition' detection.
-  StateListPtr States(new std::deque<StateInfo>(1));
-
 
   // position() is called when engine receives the "position" UCI command.
   // The function sets up the position described in the given FEN string ("fen")
   // or the starting position ("startpos") and then makes the moves given in the
   // following move list ("moves").
 
-  void position(Position& pos, istringstream& is) {
+  void position(Position& pos, istringstream& is, StateListPtr& states) {
 
     Move m;
     string token, fen;
@@ -68,14 +66,14 @@ namespace {
     else
         return;
 
-    States = StateListPtr(new std::deque<StateInfo>(1));
-    pos.set(fen, Options["UCI_Chess960"], &States->back(), Threads.main());
+    states = StateListPtr(new std::deque<StateInfo>(1)); // Drop old and create a new one
+    pos.set(fen, Options["UCI_Chess960"], &states->back(), Threads.main());
 
     // Parse move list (if any)
     while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE)
     {
-        States->push_back(StateInfo());
-        pos.do_move(m, States->back(), pos.gives_check(m));
+        states->emplace_back();
+        pos.do_move(m, states->back());
     }
   }
 
@@ -91,11 +89,11 @@ namespace {
 
     // Read option name (can contain spaces)
     while (is >> token && token != "value")
-        name += string(" ", name.empty() ? 0 : 1) + token;
+        name += (name.empty() ? "" : " ") + token;
 
     // Read option value (can contain spaces)
     while (is >> token)
-        value += string(" ", value.empty() ? 0 : 1) + token;
+        value += (value.empty() ? "" : " ") + token;
 
     if (Options.count(name))
         Options[name] = value;
@@ -108,10 +106,11 @@ namespace {
   // the thinking time and other parameters from the input string, then starts
   // the search.
 
-  void go(Position& pos, istringstream& is) {
+  void go(Position& pos, istringstream& is, StateListPtr& states) {
 
     Search::LimitsType limits;
     string token;
+    bool ponderMode = false;
 
     limits.startTime = now(); // As early as possible!
 
@@ -129,10 +128,53 @@ namespace {
         else if (token == "nodes")     is >> limits.nodes;
         else if (token == "movetime")  is >> limits.movetime;
         else if (token == "mate")      is >> limits.mate;
+        else if (token == "perft")     is >> limits.perft;
         else if (token == "infinite")  limits.infinite = 1;
-        else if (token == "ponder")    limits.ponder = 1;
+        else if (token == "ponder")    ponderMode = true;
 
-    Threads.start_thinking(pos, States, limits);
+    Threads.start_thinking(pos, states, limits, ponderMode);
+  }
+
+
+  // bench() is called when engine receives the "bench" command. Firstly
+  // a list of UCI commands is setup according to bench parameters, then
+  // it is run one by one printing a summary at the end.
+
+  void bench(Position& pos, istream& args, StateListPtr& states) {
+
+    string token;
+    uint64_t num, nodes = 0, cnt = 1;
+
+    vector<string> list = setup_bench(pos, args);
+    num = count_if(list.begin(), list.end(), [](string s) { return s.find("go ") == 0; });
+
+    TimePoint elapsed = now();
+
+    for (const auto& cmd : list)
+    {
+        istringstream is(cmd);
+        is >> skipws >> token;
+
+        if (token == "go")
+        {
+            cerr << "\nPosition: " << cnt++ << '/' << num << endl;
+            go(pos, is, states);
+            Threads.main()->wait_for_search_finished();
+            nodes += Threads.nodes_searched();
+        }
+        else if (token == "setoption")  setoption(is);
+        else if (token == "position")   position(pos, is, states);
+        else if (token == "ucinewgame") Search::clear();
+    }
+
+    elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
+
+    dbg_print(); // Just before exiting
+
+    cerr << "\n==========================="
+         << "\nTotal time (ms) : " << elapsed
+         << "\nNodes searched  : " << nodes
+         << "\nNodes/second    : " << 1000 * nodes / elapsed << endl;
   }
 
 } // namespace
@@ -148,8 +190,10 @@ void UCI::loop(int argc, char* argv[]) {
 
   Position pos;
   string token, cmd;
+  StateListPtr states(new std::deque<StateInfo>(1));
+  auto uiThread = std::make_shared<Thread>(0);
 
-  pos.set(StartFEN, false, &States->back(), Threads.main());
+  pos.set(StartFEN, false, &states->back(), uiThread.get());
 
   for (int i = 1; i < argc; ++i)
       cmd += std::string(argv[i]) + " ";
@@ -160,61 +204,42 @@ void UCI::loop(int argc, char* argv[]) {
 
       istringstream is(cmd);
 
-      token.clear(); // getline() could return empty or blank line
+      token.clear(); // Avoid a stale if getline() returns empty or blank line
       is >> skipws >> token;
 
-      // The GUI sends 'ponderhit' to tell us to ponder on the same move the
-      // opponent has played. In case Signals.stopOnPonderhit is set we are
-      // waiting for 'ponderhit' to stop the search (for instance because we
-      // already ran out of time), otherwise we should continue searching but
-      // switching from pondering to normal search.
+      // The GUI sends 'ponderhit' to tell us the user has played the expected move.
+      // So 'ponderhit' will be sent if we were told to ponder on the same move the
+      // user has played. We should continue searching but switch from pondering to
+      // normal search. In case Threads.stopOnPonderhit is set we are waiting for
+      // 'ponderhit' to stop the search, for instance if max search depth is reached.
       if (    token == "quit"
           ||  token == "stop"
-          || (token == "ponderhit" && Search::Signals.stopOnPonderhit))
-      {
-          Search::Signals.stop = true;
-          Threads.main()->start_searching(true); // Could be sleeping
-      }
+          || (token == "ponderhit" && Threads.stopOnPonderhit))
+          Threads.stop = true;
+
       else if (token == "ponderhit")
-          Search::Limits.ponder = 0; // Switch to normal search
+          Threads.ponder = false; // Switch to normal search
 
       else if (token == "uci")
           sync_cout << "id name " << engine_info(true)
                     << "\n"       << Options
                     << "\nuciok"  << sync_endl;
 
-      else if (token == "ucinewgame")
-      {
-          Search::clear();
-          Time.availableNodes = 0;
-      }
-      else if (token == "isready")    sync_cout << "readyok" << sync_endl;
-      else if (token == "go")         go(pos, is);
-      else if (token == "position")   position(pos, is);
       else if (token == "setoption")  setoption(is);
+      else if (token == "go")         go(pos, is, states);
+      else if (token == "position")   position(pos, is, states);
+      else if (token == "ucinewgame") Search::clear();
+      else if (token == "isready")    sync_cout << "readyok" << sync_endl;
 
-      // Additional custom non-UCI commands, useful for debugging
-      else if (token == "flip")       pos.flip();
-      else if (token == "bench")      benchmark(pos, is);
-      else if (token == "d")          sync_cout << pos << sync_endl;
-      else if (token == "eval")       sync_cout << Eval::trace(pos) << sync_endl;
-      else if (token == "perft")
-      {
-          int depth;
-          stringstream ss;
-
-          is >> depth;
-          ss << Options["Hash"]    << " "
-             << Options["Threads"] << " " << depth << " current perft";
-
-          benchmark(pos, ss);
-      }
+      // Additional custom non-UCI commands, mainly for debugging
+      else if (token == "flip")  pos.flip();
+      else if (token == "bench") bench(pos, is, states);
+      else if (token == "d")     sync_cout << pos << sync_endl;
+      else if (token == "eval")  sync_cout << Eval::trace(pos) << sync_endl;
       else
           sync_cout << "Unknown command: " << cmd << sync_endl;
 
-  } while (token != "quit" && argc == 1); // Passed args have one-shot behaviour
-
-  Threads.main()->wait_for_search_finished();
+  } while (token != "quit" && argc == 1); // Command line args are one-shot
 }
 
 
@@ -227,6 +252,8 @@ void UCI::loop(int argc, char* argv[]) {
 
 string UCI::value(Value v) {
 
+  assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
+
   stringstream ss;
 
   if (abs(v) < VALUE_MATE - MAX_PLY)

src/uci.h

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -49,12 +49,14 @@ public:
   Option(OnChange = nullptr);
   Option(bool v, OnChange = nullptr);
   Option(const char* v, OnChange = nullptr);
-  Option(int v, int min, int max, OnChange = nullptr);
+  Option(double v, int minv, int maxv, OnChange = nullptr);
+  Option(const char* v, const char* cur, OnChange = nullptr);
 
   Option& operator=(const std::string&);
   void operator<<(const Option&);
-  operator int() const;
+  operator double() const;
   operator std::string() const;
+  bool operator==(const char*) const;
 
 private:
   friend std::ostream& operator<<(std::ostream&, const OptionsMap&);

src/ucioption.cpp

@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -39,7 +39,7 @@ namespace UCI {
 void on_clear_hash(const Option&) { Search::clear(); }
 void on_hash_size(const Option& o) { TT.resize(o); }
 void on_logger(const Option& o) { start_logger(o); }
-void on_threads(const Option&) { Threads.read_uci_options(); }
+void on_threads(const Option& o) { Threads.set(o); }
 void on_tb_path(const Option& o) { Tablebases::init(o); }
 
 
@@ -55,11 +55,13 @@ bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const
 
 void init(OptionsMap& o) {
 
-  const int MaxHashMB = Is64Bit ? 1024 * 1024 : 2048;
+  // at most 2^32 clusters.
+  constexpr int MaxHashMB = Is64Bit ? 131072 : 2048;
 
   o["Debug Log File"]        << Option("", on_logger);
-  o["Contempt"]              << Option(0, -100, 100);
-  o["Threads"]               << Option(1, 1, 128, on_threads);
+  o["Contempt"]              << Option(24, -100, 100);
+  o["Analysis Contempt"]     << Option("Both var Off var White var Black var Both", "Both");
+  o["Threads"]               << Option(1, 1, 512, on_threads);
   o["Hash"]                  << Option(16, 1, MaxHashMB, on_hash_size);
   o["Clear Hash"]            << Option(on_clear_hash);
   o["Ponder"]                << Option(false);
@@ -67,13 +69,14 @@ void init(OptionsMap& o) {
   o["Skill Level"]           << Option(20, 0, 20);
   o["Move Overhead"]         << Option(30, 0, 5000);
   o["Minimum Thinking Time"] << Option(20, 0, 5000);
-  o["Slow Mover"]            << Option(89, 10, 1000);
+  o["Slow Mover"]            << Option(84, 10, 1000);
   o["nodestime"]             << Option(0, 0, 10000);
   o["UCI_Chess960"]          << Option(false);
+  o["UCI_AnalyseMode"]       << Option(false);
   o["SyzygyPath"]            << Option("<empty>", on_tb_path);
   o["SyzygyProbeDepth"]      << Option(1, 1, 100);
   o["Syzygy50MoveRule"]      << Option(true);
-  o["SyzygyProbeLimit"]      << Option(6, 0, 6);
+  o["SyzygyProbeLimit"]      << Option(7, 0, 7);
 }
 
 
@@ -89,11 +92,13 @@ std::ostream& operator<<(std::ostream& os, const OptionsMap& om) {
               const Option& o = it.second;
               os << "\noption name " << it.first << " type " << o.type;
 
-              if (o.type != "button")
+              if (o.type == "string" || o.type == "check" || o.type == "combo")
                   os << " default " << o.defaultValue;
 
               if (o.type == "spin")
-                  os << " min " << o.min << " max " << o.max;
+                  os << " default " << int(stof(o.defaultValue))
+                     << " min "     << o.min
+                     << " max "     << o.max;
 
               break;
           }
@@ -113,12 +118,15 @@ Option::Option(bool v, OnChange f) : type("check"), min(0), max(0), on_change(f)
 Option::Option(OnChange f) : type("button"), min(0), max(0), on_change(f)
 {}
 
-Option::Option(int v, int minv, int maxv, OnChange f) : type("spin"), min(minv), max(maxv), on_change(f)
+Option::Option(double v, int minv, int maxv, OnChange f) : type("spin"), min(minv), max(maxv), on_change(f)
 { defaultValue = currentValue = std::to_string(v); }
 
-Option::operator int() const {
+Option::Option(const char* v, const char* cur, OnChange f) : type("combo"), min(0), max(0), on_change(f)
+{ defaultValue = v; currentValue = cur; }
+
+Option::operator double() const {
   assert(type == "check" || type == "spin");
-  return (type == "spin" ? stoi(currentValue) : currentValue == "true");
+  return (type == "spin" ? stof(currentValue) : currentValue == "true");
 }
 
 Option::operator std::string() const {
@@ -126,6 +134,12 @@ Option::operator std::string() const {
   return currentValue;
 }
 
+bool Option::operator==(const char* s) const {
+  assert(type == "combo");
+  return    !CaseInsensitiveLess()(currentValue, s)
+         && !CaseInsensitiveLess()(s, currentValue);
+}
+
 
 /// operator<<() inits options and assigns idx in the correct printing order
 
@@ -148,7 +162,7 @@ Option& Option::operator=(const string& v) {
 
   if (   (type != "button" && v.empty())
       || (type == "check" && v != "true" && v != "false")
-      || (type == "spin" && (stoi(v) < min || stoi(v) > max)))
+      || (type == "spin" && (stof(v) < min || stof(v) > max)))
       return *this;
 
   if (type != "button")

tests/instrumented.sh

@@ -0,0 +1,144 @@
+#!/bin/bash
+# check for errors under valgrind or sanitizers.
+
+error()
+{
+  echo "instrumented testing failed on line $1"
+  exit 1
+}
+trap 'error ${LINENO}' ERR
+
+# define suitable post and prefixes for testing options
+case $1 in
+  --valgrind)
+    echo "valgrind testing started"
+    prefix=''
+    exeprefix='valgrind --error-exitcode=42'
+    postfix='1>/dev/null'
+    threads="1"
+  ;;
+  --valgrind-thread)
+    echo "valgrind-thread testing started"
+    prefix=''
+    exeprefix='valgrind --error-exitcode=42'
+    postfix='1>/dev/null'
+    threads="2"
+  ;;
+  --sanitizer-undefined)
+    echo "sanitizer-undefined testing started"
+    prefix='!'
+    exeprefix=''
+    postfix='2>&1 | grep "runtime error:"'
+    threads="1"
+  ;;
+  --sanitizer-thread)
+    echo "sanitizer-thread testing started"
+    prefix='!'
+    exeprefix=''
+    postfix='2>&1 | grep "WARNING: ThreadSanitizer:"'
+    threads="2"
+
+cat << EOF > tsan.supp
+race:TTEntry::move
+race:TTEntry::depth
+race:TTEntry::bound
+race:TTEntry::save
+race:TTEntry::value
+race:TTEntry::eval
+
+race:TranspositionTable::probe
+race:TranspositionTable::hashfull
+
+EOF
+
+    export TSAN_OPTIONS="suppressions=./tsan.supp"
+
+  ;;
+  *)
+    echo "unknown testing started"
+    prefix=''
+    exeprefix=''
+    postfix=''
+    threads="1"
+  ;;
+esac
+
+# simple command line testing
+for args in "eval" \
+            "go nodes 1000" \
+            "go depth 10" \
+            "go movetime 1000" \
+            "go wtime 8000 btime 8000 winc 500 binc 500" \
+            "bench 128 $threads 10 default depth"
+do
+
+   echo "$prefix $exeprefix ./stockfish $args $postfix"
+   eval "$prefix $exeprefix ./stockfish $args $postfix"
+
+done
+
+# more general testing, following an uci protocol exchange
+cat << EOF > game.exp
+ set timeout 10
+ spawn $exeprefix ./stockfish
+
+ send "uci\n"
+ expect "uciok"
+
+ send "setoption name Threads value $threads\n"
+
+ send "ucinewgame\n"
+ send "position startpos\n"
+ send "go nodes 1000\n"
+ expect "bestmove"
+
+ send "position startpos moves e2e4 e7e6\n"
+ send "go nodes 1000\n"
+ expect "bestmove"
+
+ send "position fen 5rk1/1K4p1/8/8/3B4/8/8/8 b - - 0 1\n"
+ send "go depth 30\n"
+ expect "bestmove"
+
+ send "quit\n"
+ expect eof
+
+ # return error code of the spawned program, useful for valgrind
+ lassign [wait] pid spawnid os_error_flag value
+ exit \$value
+EOF
+
+#download TB as needed
+if [ ! -d ../tests/syzygy ]; then
+   curl -sL https://api.github.com/repos/niklasf/python-chess/tarball/9b9aa13f9f36d08aadfabff872882f4ab1494e95 | tar -xzf -
+   mv niklasf-python-chess-9b9aa13 ../tests/syzygy
+fi
+
+cat << EOF > syzygy.exp
+ set timeout 240
+ spawn $exeprefix ./stockfish
+ send "uci\n"
+ send "setoption name SyzygyPath value ../tests/syzygy/\n"
+ expect "info string Found 35 tablebases" {} timeout {exit 1}
+ send "bench 128 1 10 default depth\n"
+ send "quit\n"
+ expect eof
+
+ # return error code of the spawned program, useful for valgrind
+ lassign [wait] pid spawnid os_error_flag value
+ exit \$value
+EOF
+
+for exp in game.exp syzygy.exp
+do
+
+  echo "$prefix expect $exp $postfix"
+  eval "$prefix expect $exp $postfix"
+
+  rm $exp
+
+done
+
+rm -f tsan.supp
+
+echo "instrumented testing OK"

tests/perft.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+# verify perft numbers (positions from https://chessprogramming.wikispaces.com/Perft+Results)
+
+error()
+{
+  echo "perft testing failed on line $1"
+  exit 1
+}
+trap 'error ${LINENO}' ERR
+
+echo "perft testing started"
+
+cat << EOF > perft.exp
+   set timeout 10
+   lassign \$argv pos depth result
+   spawn ./stockfish
+   send "position \$pos\\ngo perft \$depth\\n"
+   expect "Nodes searched? \$result" {} timeout {exit 1}
+   send "quit\\n"
+   expect eof
+EOF
+
+expect perft.exp startpos 5 4865609 > /dev/null
+expect perft.exp "fen r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -" 5 193690690 > /dev/null
+expect perft.exp "fen 8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -" 6 11030083 > /dev/null
+expect perft.exp "fen r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1" 5 15833292 > /dev/null
+expect perft.exp "fen rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8" 5 89941194 > /dev/null
+expect perft.exp "fen r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10" 5 164075551 > /dev/null
+
+rm perft.exp
+
+echo "perft testing OK"

tests/reprosearch.sh

@@ -0,0 +1,61 @@
+#!/bin/bash
+# verify reproducible search
+
+error()
+{
+  echo "reprosearch testing failed on line $1"
+  exit 1
+}
+trap 'error ${LINENO}' ERR
+
+echo "reprosearch testing started"
+
+# repeat two short games, separated by ucinewgame. 
+# with go nodes $nodes they should result in exactly
+# the same node count for each iteration.
+cat << EOF > repeat.exp
+ set timeout 10
+ spawn ./stockfish
+ lassign \$argv nodes
+
+ send "uci\n"
+ expect "uciok"
+
+ send "ucinewgame\n"
+ send "position startpos\n"
+ send "go nodes \$nodes\n"
+ expect "bestmove"
+
+ send "position startpos moves e2e4 e7e6\n"
+ send "go nodes \$nodes\n"
+ expect "bestmove"
+
+ send "ucinewgame\n"
+ send "position startpos\n"
+ send "go nodes \$nodes\n"
+ expect "bestmove"
+
+ send "position startpos moves e2e4 e7e6\n"
+ send "go nodes \$nodes\n"
+ expect "bestmove"
+
+ send "quit\n"
+ expect eof
+EOF
+
+# to increase the likelyhood of finding a non-reproducible case,
+# the allowed number of nodes are varied systematically
+for i in `seq 1 20`
+do
+
+  nodes=$((100*3**i/2**i))
+  echo "reprosearch testing with $nodes nodes"
+
+  # each line should appear exactly an even number of times
+  expect repeat.exp $nodes 2>&1 | grep -o "nodes [0-9]*" | sort | uniq -c | awk '{if ($1%2!=0) exit(1)}'
+
+done
+
+rm repeat.exp
+
+echo "reprosearch testing OK"

tests/signature.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+# obtain and optionally verify Bench / signature
+# if no reference is given, the output is deliberately limited to just the signature
+
+error()
+{
+  echo "running bench for signature failed on line $1"
+  exit 1
+}
+trap 'error ${LINENO}' ERR
+
+# obtain
+
+signature=`./stockfish bench 2>&1 | grep "Nodes searched  : " | awk '{print $4}'`
+
+if [ $# -gt 0 ]; then
+   # compare to given reference
+   if [ "$1" != "$signature" ]; then
+      if [ -z "$signature" ]; then
+         echo "No signature obtained from bench. Code crashed or assert triggered ?"
+      else
+         echo "signature mismatch: reference $1 obtained: $signature ."
+      fi
+      exit 1
+   else
+      echo "signature OK: $signature"
+   fi
+else
+   # just report signature
+   echo $signature
+fi