Stockfish DD

Stockfish bench signature is: 8596156

Readme.md

@@ -7,14 +7,10 @@ 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 64 CPUs, but has not been
-tested thoroughly with more than 4.  The program tries to detect the
-number of CPUs on your computer and sets the number of search threads
-accordingly, but please be aware that the detection is not always
-correct. 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. If you are using more than eight threads, it is
-recommended to raise the value of the *Min Split Depth* UCI parameter to 7.
+This version of Stockfish supports up to 64 CPUs. The engine defaults
+to one search thread 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.
 
 
 ### Files
@@ -25,7 +21,7 @@ This distribution of Stockfish consists of the following files:
 
   * Copying.txt, a text file containing the GNU General Public License.
 
-  * src/, a subdirectory containing the full source code, including a Makefile
+  * src, a subdirectory containing the full source code, including a Makefile
     that can be used to compile Stockfish on Unix-like systems. For further
     information about how to compile Stockfish yourself read section below.
 

polyglot.ini

@@ -14,22 +14,25 @@ ResignScore = 600
 
 [Engine]
 
-Use Search Log = false
+Write Debug Log = false
+Write Search Log = false
 Search Log Filename = SearchLog.txt
 Book File = book.bin
 Best Book Move = false
 Contempt Factor = 0
-Mobility (Middle Game) = 100
+Mobility (Midgame) = 100
 Mobility (Endgame) = 100
-Passed Pawns (Middle Game) = 100
+Pawn Structure (Midgame) = 100
+Pawn Structure (Endgame) = 100
+Passed Pawns (Midgame) = 100
 Passed Pawns (Endgame) = 100
 Space = 100
 Aggressiveness = 100
 Cowardice = 100
-Min Split Depth = 4
+Min Split Depth = 0
 Max Threads per Split Point = 5
 Threads = 1
-Use Sleeping Threads = false
+Idle Threads Sleep = false
 Hash = 128
 Ponder = true
 OwnBook = false
@@ -39,5 +42,6 @@ Emergency Move Horizon = 40
 Emergency Base Time = 200
 Emergency Move Time = 70
 Minimum Thinking Time = 20
+Slow Mover = 100
 UCI_Chess960 = false
 UCI_AnalyseMode = false

src/Makefile

@@ -34,8 +34,9 @@ ifeq ($(UNAME),Haiku)
 endif
 BINDIR = $(PREFIX)/bin
 
-### Built-in benchmark for pgo-builds
+### Built-in benchmark for pgo-builds and signature
 PGOBENCH = ./$(EXE) bench 32 1 10 default depth
+SIGNBENCH = ./$(EXE) bench
 
 ### Object files
 OBJS = benchmark.o bitbase.o bitboard.o book.o endgame.o evaluate.o main.o \
@@ -164,6 +165,16 @@ ifeq ($(ARCH),osx-ppc-32)
 	sse = no
 endif
 
+ifeq ($(ARCH),linux-ppc-64)
+	arch = ppc64
+	os = any
+	bits = 64
+	prefetch = no
+	bsfq = no
+	popcnt = no
+	sse = no
+endif
+
 ifeq ($(ARCH),osx-x86-64)
 	arch = x86_64
 	os = osx
@@ -231,7 +242,7 @@ ifeq ($(COMP),clang)
 endif
 
 ### 3.2 General compiler settings
-CXXFLAGS = -g -Wall -Wcast-qual -fno-exceptions -fno-rtti $(EXTRACXXFLAGS)
+CXXFLAGS = -Wall -Wcast-qual -fno-exceptions -fno-rtti $(EXTRACXXFLAGS)
 
 ifeq ($(comp),gcc)
 	CXXFLAGS += -ansi -pedantic -Wno-long-long -Wextra -Wshadow
@@ -242,7 +253,7 @@ ifeq ($(comp),mingw)
 endif
 
 ifeq ($(comp),icc)
-	CXXFLAGS += -wd383,981,1418,1419,1476,10187,10188,11505,11503 -Wcheck -Wabi -Wdeprecated -strict-ansi
+	CXXFLAGS += -diag-disable 1476,10120 -Wcheck -Wabi -Wdeprecated -strict-ansi
 endif
 
 ifeq ($(comp),clang)
@@ -262,9 +273,12 @@ endif
 
 ### On mingw use Windows threads, otherwise POSIX
 ifneq ($(comp),mingw)
-	# Haiku has pthreads in its libroot, so only link it in on other platforms
-	ifneq ($(UNAME),Haiku)
-		LDFLAGS += -lpthread
+	# On Android Bionic's C library comes with its own pthread implementation bundled in
+	ifneq ($(arch),armv7)
+		# Haiku has pthreads in its libroot, so only link it in on other platforms
+		ifneq ($(UNAME),Haiku)
+			LDFLAGS += -lpthread
+		endif
 	endif
 endif
 
@@ -275,6 +289,8 @@ endif
 ### 3.4 Debugging
 ifeq ($(debug),no)
 	CXXFLAGS += -DNDEBUG
+else
+	CXXFLAGS += -g
 endif
 
 ### 3.5 Optimization
@@ -293,7 +309,7 @@ ifeq ($(optimize),yes)
 		endif
 
 		ifeq ($(arch),armv7)
-			CXXFLAGS += -fno-gcse
+			CXXFLAGS += -fno-gcse -mthumb -march=armv7-a -mfloat-abi=softfp
 		endif
 	endif
 
@@ -305,7 +321,7 @@ ifeq ($(optimize),yes)
 		ifeq ($(os),osx)
 			CXXFLAGS += -fast -mdynamic-no-pic
 		else
-			CXXFLAGS += -O3
+			CXXFLAGS += -fast
 		endif
 	endif
 
@@ -354,6 +370,7 @@ endif
 ### needs access to the optimization flags.
 ifeq ($(comp),gcc)
 	ifeq ($(optimize),yes)
+	ifeq ($(debug),no)
 		GCC_MAJOR := `$(CXX) -dumpversion | cut -f1 -d.`
 		GCC_MINOR := `$(CXX) -dumpversion | cut -f2 -d.`
 		ifeq (1,$(shell expr \( $(GCC_MAJOR) \> 4 \) \| \( $(GCC_MAJOR) \= 4 \& $(GCC_MINOR) \>= 5 \)))
@@ -361,6 +378,7 @@ ifeq ($(comp),gcc)
 			LDFLAGS += $(CXXFLAGS)
 		endif
 	endif
+	endif
 endif
 
 ### ==========================================================================
@@ -375,44 +393,47 @@ help:
 	@echo ""
 	@echo "Supported targets:"
 	@echo ""
-	@echo "build                > Build unoptimized version"
-	@echo "profile-build        > Build PGO-optimized version"
-	@echo "strip                > Strip executable"
-	@echo "install              > Install executable"
-	@echo "clean                > Clean up"
-	@echo "testrun              > Make sample run"
+	@echo "build                   > Standard build"
+	@echo "signature-build         > Standard build with embedded signature"
+	@echo "profile-build           > PGO build"
+	@echo "signature-profile-build > PGO build with embedded signature"
+	@echo "strip                   > Strip executable"
+	@echo "install                 > Install executable"
+	@echo "clean                   > Clean up"
 	@echo ""
 	@echo "Supported archs:"
 	@echo ""
-	@echo "x86-64               > x86 64-bit"
-	@echo "x86-64-modern        > x86 64-bit with runtime support for popcnt instruction"
-	@echo "x86-32               > x86 32-bit excluding old hardware without SSE-support"
-	@echo "x86-32-old           > x86 32-bit including also very old hardware"
-	@echo "osx-ppc-64           > PPC-Mac OS X 64 bit"
-	@echo "osx-ppc-32           > PPC-Mac OS X 32 bit"
-	@echo "osx-x86-64           > x86-Mac OS X 64 bit"
-	@echo "osx-x86-32           > x86-Mac OS X 32 bit"
-	@echo "armv7                > ARMv7 32 bit"
-	@echo "general-64           > unspecified 64-bit"
-	@echo "general-32           > unspecified 32-bit"
+	@echo "x86-64                  > x86 64-bit"
+	@echo "x86-64-modern           > x86 64-bit with popcnt support"
+	@echo "x86-32                  > x86 32-bit with SSE support"
+	@echo "x86-32-old              > x86 32-bit fall back for old hardware"
+	@echo "linux-ppc-64            > PPC-Linux 64 bit"
+	@echo "osx-ppc-64              > PPC-Mac OS X 64 bit"
+	@echo "osx-ppc-32              > PPC-Mac OS X 32 bit"
+	@echo "osx-x86-64              > x86-Mac OS X 64 bit"
+	@echo "osx-x86-32              > x86-Mac OS X 32 bit"
+	@echo "armv7                   > ARMv7 32 bit"
+	@echo "general-64              > unspecified 64-bit"
+	@echo "general-32              > unspecified 32-bit"
 	@echo ""
-	@echo "Supported comps:"
+	@echo "Supported compilers:"
 	@echo ""
-	@echo "gcc                  > Gnu compiler (default)"
-	@echo "icc                  > Intel compiler"
-	@echo "mingw                > Gnu compiler with MinGW under Windows"
-	@echo "clang                > LLVM Clang compiler"
+	@echo "gcc                     > Gnu compiler (default)"
+	@echo "mingw                   > Gnu compiler with MinGW under Windows"
+	@echo "clang                   > LLVM Clang compiler"
+	@echo "icc                     > Intel compiler"
 	@echo ""
 	@echo "Non-standard targets:"
 	@echo ""
-	@echo "make hpux           >  Compile for HP-UX. Compiler = aCC"
+	@echo "make hpux               >  Compile for HP-UX. Compiler = aCC"
 	@echo ""
 	@echo "Examples. If you don't know what to do, you likely want to run: "
 	@echo ""
-	@echo "make profile-build ARCH=x86-64    (This is for 64-bit systems)"
-	@echo "make profile-build ARCH=x86-32    (This is for 32-bit systems)"
+	@echo "make build ARCH=x86-64    (This is for 64-bit systems)"
+	@echo "make build ARCH=x86-32    (This is for 32-bit systems)"
 	@echo ""
 
+.PHONY: build profile-build embed-signature
 build:
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) config-sanity
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) all
@@ -437,6 +458,18 @@ profile-build:
 	@echo "Step 4/4. Deleting profile data ..."
 	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) $(profile_clean)
 
+embed-signature:
+	@echo "Running benchmark for getting the signature ..."
+	@$(SIGNBENCH) 2>&1 | sed -n 's/Nodes searched  : \(.*\)/\/string Version\/s\/"\\(.*\\)"\/"sig-\1"\//p' > sign.txt
+	@sed -f sign.txt misc.cpp > misc2.cpp
+	@mv misc2.cpp misc.cpp
+	@rm sign.txt
+
+signature-build: build embed-signature
+	$(MAKE) ARCH=$(ARCH) COMP=$(COMP) all
+
+signature-profile-build: build embed-signature profile-build
+
 strip:
 	strip $(EXE)
 
@@ -448,9 +481,6 @@ install:
 clean:
 	$(RM) $(EXE) $(EXE).exe *.o .depend *~ core bench.txt *.gcda
 
-testrun:
-	@$(PGOBENCH)
-
 default:
 	help
 

src/benchmark.cpp

@@ -47,7 +47,21 @@ static const char* Defaults[] = {
   "3r1rk1/p5pp/bpp1pp2/8/q1PP1P2/b3P3/P2NQRPP/1R2B1K1 b - - 6 22",
   "r1q2rk1/2p1bppp/2Pp4/p6b/Q1PNp3/4B3/PP1R1PPP/2K4R w - - 2 18",
   "4k2r/1pb2ppp/1p2p3/1R1p4/3P4/2r1PN2/P4PPP/1R4K1 b - - 3 22",
-  "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26"
+  "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",
+  "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",
+  "8/1p3pp1/7p/5P1P/2k3P1/8/2K2P2/8 w - - 0 1",
+  "8/pp2r1k1/2p1p3/3pP2p/1P1P1P1P/P5KR/8/8 w - - 0 1",
+  "8/3p4/p1bk3p/Pp6/1Kp1PpPp/2P2P1P/2P5/5B2 b - - 0 1",
+  "5k2/7R/4P2p/5K2/p1r2P1p/8/8/8 b - - 0 1",
+  "6k1/6p1/P6p/r1N5/5p2/7P/1b3PP1/4R1K1 w - - 0 1",
+  "1r3k2/4q3/2Pp3b/3Bp3/2Q2p2/1p1P2P1/1P2KP2/3N4 w - - 0 1",
+  "6k1/4pp1p/3p2p1/P1pPb3/R7/1r2P1PP/3B1P2/6K1 w - - 0 1",
+  "8/3p3B/5p2/5P2/p7/PP5b/k7/6K1 w - - 0 1"
 };
 
 
@@ -68,7 +82,7 @@ void benchmark(const Position& current, istream& is) {
   // Assign default values to missing arguments
   string ttSize    = (is >> token) ? token : "32";
   string threads   = (is >> token) ? token : "1";
-  string limit     = (is >> token) ? token : "12";
+  string limit     = (is >> token) ? token : "13";
   string fenFile   = (is >> token) ? token : "default";
   string limitType = (is >> token) ? token : "depth";
 
@@ -89,7 +103,7 @@ void benchmark(const Position& current, istream& is) {
       limits.depth = atoi(limit.c_str());
 
   if (fenFile == "default")
-      fens.assign(Defaults, Defaults + 16);
+      fens.assign(Defaults, Defaults + 30);
 
   else if (fenFile == "current")
       fens.push_back(current.fen());
@@ -116,9 +130,9 @@ void benchmark(const Position& current, istream& is) {
   Search::StateStackPtr st;
   Time::point elapsed = Time::now();
 
-  for (size_t i = 0; i < fens.size(); i++)
+  for (size_t i = 0; i < fens.size(); ++i)
   {
-      Position pos(fens[i], Options["UCI_Chess960"], Threads.main_thread());
+      Position pos(fens[i], Options["UCI_Chess960"], Threads.main());
 
       cerr << "\nPosition: " << i + 1 << '/' << fens.size() << endl;
 

src/bitbase.cpp

@@ -39,9 +39,9 @@ namespace {
   // bit  6-11: black king square (from SQ_A1 to SQ_H8)
   // bit    12: side to move (WHITE or BLACK)
   // bit 13-14: white pawn file (from FILE_A to FILE_D)
-  // bit 15-17: white pawn 6 - rank (from 6 - RANK_7 to 6 - RANK_2)
+  // bit 15-17: white pawn RANK_7 - rank (from RANK_7 - RANK_7 to RANK_7 - RANK_2)
   unsigned index(Color us, Square bksq, Square wksq, Square psq) {
-    return wksq + (bksq << 6) + (us << 12) + (file_of(psq) << 13) + ((6 - rank_of(psq)) << 15);
+    return wksq + (bksq << 6) + (us << 12) + (file_of(psq) << 13) + ((RANK_7 - rank_of(psq)) << 15);
   }
 
   enum Result {
@@ -55,8 +55,8 @@ namespace {
 
   struct KPKPosition {
 
-    operator Result() const { return res; }
-    Result classify_leaf(unsigned idx);
+    KPKPosition(unsigned idx);
+    operator Result() const { return result; }
     Result classify(const std::vector<KPKPosition>& db)
     { return us == WHITE ? classify<WHITE>(db) : classify<BLACK>(db); }
 
@@ -65,7 +65,7 @@ namespace {
 
     Color us;
     Square bksq, wksq, psq;
-    Result res;
+    Result result;
   };
 
 } // namespace
@@ -83,21 +83,21 @@ bool Bitbases::probe_kpk(Square wksq, Square wpsq, Square bksq, Color us) {
 void Bitbases::init_kpk() {
 
   unsigned idx, repeat = 1;
-  std::vector<KPKPosition> db(IndexMax);
+  std::vector<KPKPosition> db;
+  db.reserve(IndexMax);
 
   // Initialize db with known win / draw positions
-  for (idx = 0; idx < IndexMax; idx++)
-      db[idx].classify_leaf(idx);
+  for (idx = 0; idx < IndexMax; ++idx)
+      db.push_back(KPKPosition(idx));
 
   // Iterate through the positions until no more of the unknown positions can be
   // changed to either wins or draws (15 cycles needed).
   while (repeat)
-      for (repeat = idx = 0; idx < IndexMax; idx++)
-          if (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN)
-              repeat = 1;
+      for (repeat = idx = 0; idx < IndexMax; ++idx)
+          repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
 
   // Map 32 results into one KPKBitbase[] entry
-  for (idx = 0; idx < IndexMax; idx++)
+  for (idx = 0; idx < IndexMax; ++idx)
       if (db[idx] == WIN)
           KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
 }
@@ -105,34 +105,32 @@ void Bitbases::init_kpk() {
 
 namespace {
 
-  Result KPKPosition::classify_leaf(unsigned idx) {
+  KPKPosition::KPKPosition(unsigned idx) {
 
-    wksq = Square((idx >> 0) & 0x3F);
-    bksq = Square((idx >> 6) & 0x3F);
-    us   = Color((idx >> 12) & 0x01);
-    psq  = File((idx >> 13) & 3) | Rank(6 - (idx >> 15));
+    wksq = Square((idx >>  0) & 0x3F);
+    bksq = Square((idx >>  6) & 0x3F);
+    us   = Color ((idx >> 12) & 0x01);
+    psq  = File  ((idx >> 13) & 0x03) | Rank(RANK_7 - (idx >> 15));
+    result  = UNKNOWN;
 
     // Check if two pieces are on the same square or if a king can be captured
-    if (   wksq == psq || wksq == bksq || bksq == psq
-        || (StepAttacksBB[KING][wksq] & bksq)
+    if (   square_distance(wksq, bksq) <= 1 || wksq == psq || bksq == psq
         || (us == WHITE && (StepAttacksBB[PAWN][psq] & bksq)))
-        return res = INVALID;
+        result = INVALID;
 
-    if (us == WHITE)
+    else if (us == WHITE)
     {
         // Immediate win if pawn can be promoted without getting captured
         if (   rank_of(psq) == RANK_7
             && wksq != psq + DELTA_N
             && (   square_distance(bksq, psq + DELTA_N) > 1
                 ||(StepAttacksBB[KING][wksq] & (psq + DELTA_N))))
-            return res = WIN;
+            result = WIN;
     }
     // Immediate draw if is stalemate or king captures undefended pawn
     else if (  !(StepAttacksBB[KING][bksq] & ~(StepAttacksBB[KING][wksq] | StepAttacksBB[PAWN][psq]))
              || (StepAttacksBB[KING][bksq] & psq & ~StepAttacksBB[KING][wksq]))
-        return res = DRAW;
-
-    return res = UNKNOWN;
+        result = DRAW;
   }
 
   template<Color Us>
@@ -148,26 +146,28 @@ namespace {
     // as WIN, the position is classified WIN otherwise the current position is
     // classified UNKNOWN.
 
+    const Color Them = (Us == WHITE ? BLACK : WHITE);
+
     Result r = INVALID;
     Bitboard b = StepAttacksBB[KING][Us == WHITE ? wksq : bksq];
 
     while (b)
-        r |= Us == WHITE ? db[index(~Us, bksq, pop_lsb(&b), psq)]
-                         : db[index(~Us, pop_lsb(&b), wksq, psq)];
+        r |= Us == WHITE ? db[index(Them, bksq, pop_lsb(&b), psq)]
+                         : db[index(Them, pop_lsb(&b), wksq, psq)];
 
     if (Us == WHITE && rank_of(psq) < RANK_7)
     {
         Square s = psq + DELTA_N;
         r |= db[index(BLACK, bksq, wksq, s)]; // Single push
 
-        if (rank_of(s) == RANK_3 && s != wksq && s != bksq)
+        if (rank_of(psq) == RANK_2 && s != wksq && s != bksq)
             r |= db[index(BLACK, bksq, wksq, s + DELTA_N)]; // Double push
     }
 
     if (Us == WHITE)
-        return res = r & WIN  ? WIN  : r & UNKNOWN ? UNKNOWN : DRAW;
+        return result = r & WIN  ? WIN  : r & UNKNOWN ? UNKNOWN : DRAW;
     else
-        return res = r & DRAW ? DRAW : r & UNKNOWN ? UNKNOWN : WIN;
+        return result = r & DRAW ? DRAW : r & UNKNOWN ? UNKNOWN : WIN;
   }
 
 } // namespace

src/bitboard.cpp

@@ -42,14 +42,14 @@ Bitboard SquareBB[SQUARE_NB];
 Bitboard FileBB[FILE_NB];
 Bitboard RankBB[RANK_NB];
 Bitboard AdjacentFilesBB[FILE_NB];
-Bitboard ThisAndAdjacentFilesBB[FILE_NB];
 Bitboard InFrontBB[COLOR_NB][RANK_NB];
 Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
 Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
+Bitboard LineBB[SQUARE_NB][SQUARE_NB];
 Bitboard DistanceRingsBB[SQUARE_NB][8];
 Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
 Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
-Bitboard AttackSpanMask[COLOR_NB][SQUARE_NB];
+Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
 Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
 
 int SquareDistance[SQUARE_NB][SQUARE_NB];
@@ -84,7 +84,7 @@ namespace {
 /// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
 /// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
 
-#if !defined(USE_BSFQ)
+#ifndef USE_BSFQ
 
 Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; }
 
@@ -123,7 +123,7 @@ Square msb(Bitboard b) {
   return (Square)(result + MS1BTable[b32]);
 }
 
-#endif // !defined(USE_BSFQ)
+#endif // ifndef USE_BSFQ
 
 
 /// Bitboards::print() prints a bitboard in an easily readable format to the
@@ -133,11 +133,11 @@ void Bitboards::print(Bitboard b) {
 
   sync_cout;
 
-  for (Rank rank = RANK_8; rank >= RANK_1; rank--)
+  for (Rank rank = RANK_8; rank >= RANK_1; --rank)
   {
       std::cout << "+---+---+---+---+---+---+---+---+" << '\n';
 
-      for (File file = FILE_A; file <= FILE_H; file++)
+      for (File file = FILE_A; file <= FILE_H; ++file)
           std::cout << "| " << (b & (file | rank) ? "X " : "  ");
 
       std::cout << "|\n";
@@ -151,59 +151,54 @@ void Bitboards::print(Bitboard b) {
 
 void Bitboards::init() {
 
-  for (int k = 0, i = 0; i < 8; i++)
+  for (int k = 0, i = 0; i < 8; ++i)
       while (k < (2 << i))
           MS1BTable[k++] = i;
 
-  for (int i = 0; i < 64; i++)
+  for (int i = 0; i < 64; ++i)
       BSFTable[bsf_index(1ULL << i)] = Square(i);
 
-  for (Square s = SQ_A1; s <= SQ_H8; s++)
+  for (Square s = SQ_A1; s <= SQ_H8; ++s)
       SquareBB[s] = 1ULL << s;
 
   FileBB[FILE_A] = FileABB;
   RankBB[RANK_1] = Rank1BB;
 
-  for (int i = 1; i < 8; i++)
+  for (int i = 1; i < 8; ++i)
   {
       FileBB[i] = FileBB[i - 1] << 1;
       RankBB[i] = RankBB[i - 1] << 8;
   }
 
-  for (File f = FILE_A; f <= FILE_H; f++)
-  {
+  for (File f = FILE_A; f <= FILE_H; ++f)
       AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0);
-      ThisAndAdjacentFilesBB[f] = FileBB[f] | AdjacentFilesBB[f];
-  }
 
-  for (Rank r = RANK_1; r < RANK_8; r++)
+  for (Rank r = RANK_1; r < RANK_8; ++r)
       InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]);
 
-  for (Color c = WHITE; c <= BLACK; c++)
-      for (Square s = SQ_A1; s <= SQ_H8; s++)
+  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)];
-          PassedPawnMask[c][s] = InFrontBB[c][rank_of(s)] & ThisAndAdjacentFilesBB[file_of(s)];
-          AttackSpanMask[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];
+          PawnAttackSpan[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)];
+          PassedPawnMask[c][s] = ForwardBB[c][s] | PawnAttackSpan[c][s];
       }
 
-  for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
-      for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+  for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
+      for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
+      {
           SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2));
-
-  for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
-      for (int d = 1; d < 8; d++)
-          for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
-              if (SquareDistance[s1][s2] == d)
-                  DistanceRingsBB[s1][d - 1] |= s2;
+          if (s1 != s2)
+             DistanceRingsBB[s1][SquareDistance[s1][s2] - 1] |= s2;
+      }
 
   int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },
                      {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } };
 
-  for (Color c = WHITE; c <= BLACK; c++)
-      for (PieceType pt = PAWN; pt <= KING; pt++)
-          for (Square s = SQ_A1; s <= SQ_H8; s++)
-              for (int k = 0; steps[pt][k]; k++)
+  for (Color c = WHITE; c <= BLACK; ++c)
+      for (PieceType pt = PAWN; pt <= KING; ++pt)
+          for (Square s = SQ_A1; s <= SQ_H8; ++s)
+              for (int k = 0; steps[pt][k]; ++k)
               {
                   Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]);
 
@@ -217,20 +212,23 @@ void Bitboards::init() {
   init_magics(RTable, RAttacks, RMagics, RMasks, RShifts, RDeltas, magic_index<ROOK>);
   init_magics(BTable, BAttacks, BMagics, BMasks, BShifts, BDeltas, magic_index<BISHOP>);
 
-  for (Square s = SQ_A1; s <= SQ_H8; s++)
+  for (Square s = SQ_A1; s <= SQ_H8; ++s)
   {
       PseudoAttacks[QUEEN][s]  = PseudoAttacks[BISHOP][s] = attacks_bb<BISHOP>(s, 0);
       PseudoAttacks[QUEEN][s] |= PseudoAttacks[  ROOK][s] = attacks_bb<  ROOK>(s, 0);
   }
 
-  for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
-      for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+  for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
+      for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
           if (PseudoAttacks[QUEEN][s1] & s2)
           {
               Square delta = (s2 - s1) / square_distance(s1, s2);
 
               for (Square s = s1 + delta; s != s2; s += delta)
                   BetweenBB[s1][s2] |= s;
+
+              PieceType pt = (PseudoAttacks[BISHOP][s1] & s2) ? BISHOP : ROOK;
+              LineBB[s1][s2] = (PseudoAttacks[pt][s1] & PseudoAttacks[pt][s2]) | s1 | s2;
           }
 }
 
@@ -241,7 +239,7 @@ namespace {
 
     Bitboard attack = 0;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 4; ++i)
         for (Square s = sq + deltas[i];
              is_ok(s) && square_distance(s, s - deltas[i]) == 1;
              s += deltas[i])
@@ -287,7 +285,7 @@ namespace {
     // attacks[s] is a pointer to the beginning of the attacks table for square 's'
     attacks[SQ_A1] = table;
 
-    for (Square s = SQ_A1; s <= SQ_H8; s++)
+    for (Square s = SQ_A1; s <= SQ_H8; ++s)
     {
         // Board edges are not considered in the relevant occupancies
         edges = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s));
@@ -322,13 +320,13 @@ namespace {
             do magics[s] = pick_random(rk, booster);
             while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
 
-            memset(attacks[s], 0, size * sizeof(Bitboard));
+            std::memset(attacks[s], 0, size * sizeof(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 (i = 0; i < size; i++)
+            for (i = 0; i < size; ++i)
             {
                 Bitboard& attack = attacks[s][index(s, occupancy[i])];
 

src/bitboard.h

@@ -18,7 +18,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(BITBOARD_H_INCLUDED)
+#ifndef BITBOARD_H_INCLUDED
 #define BITBOARD_H_INCLUDED
 
 #include "types.h"
@@ -37,6 +37,24 @@ bool probe_kpk(Square wksq, Square wpsq, Square bksq, Color us);
 
 }
 
+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;
+
+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);
+
 CACHE_LINE_ALIGNMENT
 
 extern Bitboard RMasks[SQUARE_NB];
@@ -53,17 +71,19 @@ extern Bitboard SquareBB[SQUARE_NB];
 extern Bitboard FileBB[FILE_NB];
 extern Bitboard RankBB[RANK_NB];
 extern Bitboard AdjacentFilesBB[FILE_NB];
-extern Bitboard ThisAndAdjacentFilesBB[FILE_NB];
 extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
 extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
 extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
+extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
 extern Bitboard DistanceRingsBB[SQUARE_NB][8];
 extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
 extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
-extern Bitboard AttackSpanMask[COLOR_NB][SQUARE_NB];
+extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
 extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
 
-const Bitboard BlackSquares = 0xAA55AA55AA55AA55ULL;
+extern int SquareDistance[SQUARE_NB][SQUARE_NB];
+
+const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
 
 /// 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.
@@ -88,13 +108,34 @@ inline Bitboard operator^(Bitboard b, Square s) {
   return b ^ SquareBB[s];
 }
 
-
-/// more_than_one() returns true if in 'b' there is more than one bit set
-
 inline bool more_than_one(Bitboard b) {
   return b & (b - 1);
 }
 
+inline int square_distance(Square s1, Square s2) {
+  return SquareDistance[s1][s2];
+}
+
+inline int file_distance(Square s1, Square s2) {
+  return abs(file_of(s1) - file_of(s2));
+}
+
+inline int rank_distance(Square s1, Square s2) {
+  return abs(rank_of(s1) - rank_of(s2));
+}
+
+
+/// shift_bb() moves bitboard one step along direction Delta. Mainly for pawns.
+
+template<Square Delta>
+inline Bitboard shift_bb(Bitboard b) {
+
+  return  Delta == DELTA_N  ?  b             << 8 : Delta == DELTA_S  ?  b             >> 8
+        : Delta == DELTA_NE ? (b & ~FileHBB) << 9 : Delta == DELTA_SE ? (b & ~FileHBB) >> 7
+        : Delta == DELTA_NW ? (b & ~FileABB) << 7 : Delta == DELTA_SW ? (b & ~FileABB) >> 9
+        : 0;
+}
+
 
 /// rank_bb() and file_bb() take a file or a square as input and return
 /// a bitboard representing all squares on the given file or rank.
@@ -116,7 +157,7 @@ inline Bitboard file_bb(Square s) {
 }
 
 
-/// adjacent_files_bb takes a file as input and returns a bitboard representing
+/// adjacent_files_bb() takes a file as input and returns a bitboard representing
 /// all squares on the adjacent files.
 
 inline Bitboard adjacent_files_bb(File f) {
@@ -124,30 +165,17 @@ inline Bitboard adjacent_files_bb(File f) {
 }
 
 
-/// this_and_adjacent_files_bb takes a file as input and returns a bitboard
-/// representing all squares on the given and adjacent files.
-
-inline Bitboard this_and_adjacent_files_bb(File f) {
-  return ThisAndAdjacentFilesBB[f];
-}
-
-
-/// in_front_bb() takes a color and a rank or square as input, and returns a
-/// bitboard representing all the squares on all ranks in front of the rank
-/// (or square), from the given color's point of view.  For instance,
-/// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
-/// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
+/// in_front_bb() takes a color and a rank as input, and returns a bitboard
+/// representing all the squares on all ranks in front of the rank, from the
+/// given color's point of view. For instance, in_front_bb(BLACK, RANK_3) will
+/// give all squares on ranks 1 and 2.
 
 inline Bitboard in_front_bb(Color c, Rank r) {
   return InFrontBB[c][r];
 }
 
-inline Bitboard in_front_bb(Color c, Square s) {
-  return InFrontBB[c][rank_of(s)];
-}
 
-
-/// between_bb returns a bitboard representing all squares between two squares.
+/// between_bb() returns a bitboard representing all squares between two squares.
 /// For instance, between_bb(SQ_C4, SQ_F7) returns a bitboard with the bits for
 /// square d5 and e6 set.  If s1 and s2 are not on the same line, file or diagonal,
 /// 0 is returned.
@@ -157,7 +185,7 @@ inline Bitboard between_bb(Square s1, Square s2) {
 }
 
 
-/// forward_bb takes a color and a square as input, and returns a bitboard
+/// forward_bb() takes a color and a square as input, and returns a bitboard
 /// representing all squares along the line in front of the square, from the
 /// point of view of the given color. Definition of the table is:
 /// ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s)
@@ -167,40 +195,39 @@ inline Bitboard forward_bb(Color c, Square s) {
 }
 
 
-/// passed_pawn_mask takes a color and a square as input, and returns a
+/// pawn_attack_span() takes a color and a square as input, and returns a bitboard
+/// representing all squares that can be attacked by a pawn of the given color
+/// when it moves along its file starting from the given square. Definition is:
+/// PawnAttackSpan[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
+
+inline Bitboard pawn_attack_span(Color c, Square s) {
+  return PawnAttackSpan[c][s];
+}
+
+
+/// passed_pawn_mask() takes a color and a square as input, and returns a
 /// bitboard mask which can be used to test if a pawn of the given color on
 /// the given square is a passed pawn. Definition of the table is:
-/// PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(s)
+/// PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_bb(c, s)
 
 inline Bitboard passed_pawn_mask(Color c, Square s) {
   return PassedPawnMask[c][s];
 }
 
 
-/// attack_span_mask takes a color and a square as input, and returns a bitboard
-/// representing all squares that can be attacked by a pawn of the given color
-/// when it moves along its file starting from the given square. Definition is:
-/// AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
+/// squares_of_color() returns a bitboard representing all squares with the same
+/// color of the given square.
 
-inline Bitboard attack_span_mask(Color c, Square s) {
-  return AttackSpanMask[c][s];
+inline Bitboard squares_of_color(Square s) {
+  return DarkSquares & s ? DarkSquares : ~DarkSquares;
 }
 
 
-/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
+/// aligned() returns true if the squares s1, s2 and s3 are aligned
 /// either on a straight or on a diagonal line.
 
-inline bool squares_aligned(Square s1, Square s2, Square s3) {
-  return  (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
-        & (     SquareBB[s1] |      SquareBB[s2] |      SquareBB[s3]);
-}
-
-
-/// same_color_squares() returns a bitboard representing all squares with
-/// the same color of the given square.
-
-inline Bitboard same_color_squares(Square s) {
-  return BlackSquares & s ? BlackSquares : ~BlackSquares;
+inline bool aligned(Square s1, Square s2, Square s3) {
+  return LineBB[s1][s2] & s3;
 }
 
 
@@ -231,7 +258,7 @@ inline Bitboard attacks_bb(Square s, Bitboard occ) {
 /// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
 /// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
 
-#if defined(USE_BSFQ)
+#ifdef USE_BSFQ
 
 #  if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
 
@@ -284,7 +311,7 @@ FORCE_INLINE Square pop_lsb(Bitboard* b) {
   return s;
 }
 
-#else // if !defined(USE_BSFQ)
+#else // if defined(USE_BSFQ)
 
 extern Square msb(Bitboard b);
 extern Square lsb(Bitboard b);
@@ -292,4 +319,10 @@ extern Square pop_lsb(Bitboard* b);
 
 #endif
 
-#endif // !defined(BITBOARD_H_INCLUDED)
+/// frontmost_sq() and backmost_sq() find the square corresponding to the
+/// most/least advanced bit relative to the given color.
+
+inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
+inline Square  backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(b); }
+
+#endif // #ifndef BITBOARD_H_INCLUDED

src/bitcount.h

@@ -18,7 +18,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(BITCOUNT_H_INCLUDED)
+#ifndef BITCOUNT_H_INCLUDED
 #define BITCOUNT_H_INCLUDED
 
 #include <cassert>
@@ -81,7 +81,7 @@ inline int popcount<CNT_32_MAX15>(Bitboard b) {
 template<>
 inline int popcount<CNT_HW_POPCNT>(Bitboard b) {
 
-#if !defined(USE_POPCNT)
+#ifndef USE_POPCNT
 
   assert(false);
   return b != 0; // Avoid 'b not used' warning
@@ -102,4 +102,4 @@ inline int popcount<CNT_HW_POPCNT>(Bitboard b) {
 #endif
 }
 
-#endif // !defined(BITCOUNT_H_INCLUDED)
+#endif // #ifndef BITCOUNT_H_INCLUDED

src/book.cpp

@@ -361,7 +361,7 @@ PolyglotBook::~PolyglotBook() { if (is_open()) close(); }
 template<typename T> PolyglotBook& PolyglotBook::operator>>(T& n) {
 
   n = 0;
-  for (size_t i = 0; i < sizeof(T); i++)
+  for (size_t i = 0; i < sizeof(T); ++i)
       n = T((n << 8) + ifstream::get());
 
   return *this;
@@ -413,7 +413,7 @@ Move PolyglotBook::probe(const Position& pos, const string& fName, bool pickBest
       // Choose book move according to its score. If a move has a very
       // high score it has higher probability to be choosen than a move
       // with lower score. Note that first entry is always chosen.
-      if (   (sum && rkiss.rand<unsigned>() % sum < e.count)
+      if (   (!pickBest && sum && rkiss.rand<unsigned>() % sum < e.count)
           || (pickBest && e.count == best))
           move = Move(e.move);
   }
@@ -436,9 +436,9 @@ Move PolyglotBook::probe(const Position& pos, const string& fName, bool pickBest
       move = make<PROMOTION>(from_sq(move), to_sq(move), PieceType(pt + 1));
 
   // Add 'special move' flags and verify it is legal
-  for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
-      if (move == (ml.move() ^ type_of(ml.move())))
-          return ml.move();
+  for (MoveList<LEGAL> it(pos); *it; ++it)
+      if (move == (*it ^ type_of(*it)))
+          return *it;
 
   return MOVE_NONE;
 }

src/book.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(BOOK_H_INCLUDED)
+#ifndef BOOK_H_INCLUDED
 #define BOOK_H_INCLUDED
 
 #include <fstream>
@@ -42,4 +42,4 @@ private:
   std::string fileName;
 };
 
-#endif // !defined(BOOK_H_INCLUDED)
+#endif // #ifndef BOOK_H_INCLUDED

src/endgame.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(ENDGAME_H_INCLUDED)
+#ifndef ENDGAME_H_INCLUDED
 #define ENDGAME_H_INCLUDED
 
 #include <map>
@@ -33,6 +33,7 @@ enum EndgameType {
 
   // Evaluation functions
 
+  KNNK,  // KNN vs K
   KXK,   // Generic "mate lone king" eval
   KBNK,  // KBN vs K
   KPK,   // KP vs K
@@ -42,7 +43,6 @@ enum EndgameType {
   KQKP,  // KQ vs KP
   KQKR,  // KQ vs KR
   KBBKN, // KBB vs KN
-  KNNK,  // KNN vs K
   KmmKm, // K and two minors vs K and one or two minors
 
 
@@ -52,6 +52,7 @@ enum EndgameType {
   KBPsK,   // KB+pawns vs K
   KQKRPs,  // KQ vs KR+pawns
   KRPKR,   // KRP vs KR
+  KRPKB,   // KRP vs KB
   KRPPKRP, // KRPP vs KRP
   KPsK,    // King and pawns vs king
   KBPKB,   // KBP vs KB
@@ -85,12 +86,12 @@ struct EndgameBase {
 template<EndgameType E, typename T = typename eg_fun<(E > SCALE_FUNS)>::type>
 struct Endgame : public EndgameBase<T> {
 
-  explicit Endgame(Color c) : strongerSide(c), weakerSide(~c) {}
-  Color color() const { return strongerSide; }
+  explicit Endgame(Color c) : strongSide(c), weakSide(~c) {}
+  Color color() const { return strongSide; }
   T operator()(const Position&) const;
 
 private:
-  Color strongerSide, weakerSide;
+  const Color strongSide, weakSide;
 };
 
 
@@ -119,4 +120,4 @@ public:
   { return eg = map(eg).count(key) ? map(eg)[key] : NULL; }
 };
 
-#endif // !defined(ENDGAME_H_INCLUDED)
+#endif // #ifndef ENDGAME_H_INCLUDED

src/evaluate.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(EVALUATE_H_INCLUDED)
+#ifndef EVALUATE_H_INCLUDED
 #define EVALUATE_H_INCLUDED
 
 #include "types.h"
@@ -27,9 +27,9 @@ class Position;
 namespace Eval {
 
 extern void init();
-extern Value evaluate(const Position& pos, Value& margin);
+extern Value evaluate(const Position& pos);
 extern std::string trace(const Position& pos);
 
 }
 
-#endif // !defined(EVALUATE_H_INCLUDED)
+#endif // #ifndef EVALUATE_H_INCLUDED

src/main.cpp

@@ -34,16 +34,17 @@ int main(int argc, char* argv[]) {
 
   UCI::init(Options);
   Bitboards::init();
-  Zobrist::init();
+  Position::init();
   Bitbases::init_kpk();
   Search::init();
+  Pawns::init();
   Eval::init();
   Threads.init();
   TT.set_size(Options["Hash"]);
 
   std::string args;
 
-  for (int i = 1; i < argc; i++)
+  for (int i = 1; i < argc; ++i)
       args += std::string(argv[i]) + " ";
 
   UCI::loop(args);

src/material.cpp

@@ -35,31 +35,29 @@ namespace {
   const int NoPawnsSF[4] = { 6, 12, 32 };
 
   // Polynomial material balance parameters
-  const Value RedundantQueenPenalty = Value(320);
-  const Value RedundantRookPenalty  = Value(554);
 
   //                                  pair  pawn knight bishop rook queen
-  const int LinearCoefficients[6] = { 1617, -162, -1172, -190,  105,  26 };
+  const int LinearCoefficients[6] = { 1852, -162, -1122, -183,  249, -52 };
 
   const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
     // pair pawn knight bishop rook queen
-    {   7                               }, // Bishop pair
+    {   0                               }, // Bishop pair
     {  39,    2                         }, // Pawn
     {  35,  271,  -4                    }, // Knight
-    {   7,  105,   4,    7              }, // Bishop
-    { -27,   -2,  46,   100,   56       }, // Rook
-    {  58,   29,  83,   148,   -3,  -25 }  // Queen
+    {   0,  105,   4,    0              }, // Bishop
+    { -27,   -2,  46,   100,  -141      }, // Rook
+    {  58,   29,  83,   148,  -163,   0 }  // Queen
   };
 
   const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = {
     //           THEIR PIECES
     // pair pawn knight bishop rook queen
-    {  41                               }, // Bishop pair
-    {  37,   41                         }, // Pawn
-    {  10,   62,  41                    }, // Knight      OUR PIECES
-    {  57,   64,  39,    41             }, // Bishop
-    {  50,   40,  23,   -22,   41       }, // Rook
-    { 106,  101,   3,   151,  171,   41 }  // Queen
+    {   0                               }, // Bishop pair
+    {  37,    0                         }, // Pawn
+    {  10,   62,   0                    }, // Knight      OUR PIECES
+    {  57,   64,  39,     0             }, // Bishop
+    {  50,   40,  23,   -22,    0       }, // Rook
+    { 106,  101,   3,   151,  171,    0 }  // Queen
   };
 
   // Endgame evaluation and scaling functions accessed direcly and not through
@@ -75,24 +73,24 @@ namespace {
   // Helper templates used to detect a given material distribution
   template<Color Us> bool is_KXK(const Position& pos) {
     const Color Them = (Us == WHITE ? BLACK : WHITE);
-    return   pos.non_pawn_material(Them) == VALUE_ZERO
-          && pos.piece_count(Them, PAWN) == 0
-          && pos.non_pawn_material(Us)   >= RookValueMg;
+    return  !pos.count<PAWN>(Them)
+          && pos.non_pawn_material(Them) == VALUE_ZERO
+          && pos.non_pawn_material(Us) >= RookValueMg;
   }
 
   template<Color Us> bool is_KBPsKs(const Position& pos) {
-    return   pos.non_pawn_material(Us)   == BishopValueMg
-          && pos.piece_count(Us, BISHOP) == 1
-          && pos.piece_count(Us, PAWN)   >= 1;
+    return   pos.non_pawn_material(Us) == BishopValueMg
+          && pos.count<BISHOP>(Us) == 1
+          && pos.count<PAWN  >(Us) >= 1;
   }
 
   template<Color Us> bool is_KQKRPs(const Position& pos) {
     const Color Them = (Us == WHITE ? BLACK : WHITE);
-    return   pos.piece_count(Us, PAWN)    == 0
-          && pos.non_pawn_material(Us)    == QueenValueMg
-          && pos.piece_count(Us, QUEEN)   == 1
-          && pos.piece_count(Them, ROOK)  == 1
-          && pos.piece_count(Them, PAWN)  >= 1;
+    return  !pos.count<PAWN>(Us)
+          && pos.non_pawn_material(Us) == QueenValueMg
+          && pos.count<QUEEN>(Us)  == 1
+          && pos.count<ROOK>(Them) == 1
+          && pos.count<PAWN>(Them) >= 1;
   }
 
   /// imbalance() calculates imbalance comparing piece count of each
@@ -106,14 +104,8 @@ namespace {
     int pt1, pt2, pc, v;
     int value = 0;
 
-    // Redundancy of major pieces, formula based on Kaufman's paper
-    // "The Evaluation of Material Imbalances in Chess"
-    if (pieceCount[Us][ROOK] > 0)
-        value -=  RedundantRookPenalty * (pieceCount[Us][ROOK] - 1)
-                + RedundantQueenPenalty * pieceCount[Us][QUEEN];
-
     // Second-degree polynomial material imbalance by Tord Romstad
-    for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
+    for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
     {
         pc = pieceCount[Us][pt1];
         if (!pc)
@@ -121,7 +113,7 @@ namespace {
 
         v = LinearCoefficients[pt1];
 
-        for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+        for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
             v +=  QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
                 + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
 
@@ -150,7 +142,7 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
   if (e->key == key)
       return e;
 
-  memset(e, 0, sizeof(Entry));
+  std::memset(e, 0, sizeof(Entry));
   e->key = key;
   e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;
   e->gamePhase = game_phase(pos);
@@ -180,8 +172,8 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
       assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP)));
       assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP)));
 
-      if (   pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
-          && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
+      if (   pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE) <= 2
+          && pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK) <= 2)
       {
           e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
           return e;
@@ -221,17 +213,17 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
 
   if (npm_w + npm_b == VALUE_ZERO)
   {
-      if (pos.piece_count(BLACK, PAWN) == 0)
+      if (!pos.count<PAWN>(BLACK))
       {
-          assert(pos.piece_count(WHITE, PAWN) >= 2);
+          assert(pos.count<PAWN>(WHITE) >= 2);
           e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
       }
-      else if (pos.piece_count(WHITE, PAWN) == 0)
+      else if (!pos.count<PAWN>(WHITE))
       {
-          assert(pos.piece_count(BLACK, PAWN) >= 2);
+          assert(pos.count<PAWN>(BLACK) >= 2);
           e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
       }
-      else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1)
+      else if (pos.count<PAWN>(WHITE) == 1 && pos.count<PAWN>(BLACK) == 1)
       {
           // This is a special case because we set scaling functions
           // for both colors instead of only one.
@@ -240,36 +232,37 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
       }
   }
 
-  // No pawns makes it difficult to win, even with a material advantage
-  if (pos.piece_count(WHITE, PAWN) == 0 && npm_w - npm_b <= BishopValueMg)
+  // No pawns makes it difficult to win, even with a material advantage. This
+  // catches some trivial draws like KK, KBK and KNK
+  if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
   {
       e->factor[WHITE] = (uint8_t)
-      (npm_w == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.piece_count(WHITE, BISHOP), 2)]);
+      (npm_w == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count<BISHOP>(WHITE), 2)]);
   }
 
-  if (pos.piece_count(BLACK, PAWN) == 0 && npm_b - npm_w <= BishopValueMg)
+  if (!pos.count<PAWN>(BLACK) && npm_b - npm_w <= BishopValueMg)
   {
       e->factor[BLACK] = (uint8_t)
-      (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.piece_count(BLACK, BISHOP), 2)]);
+      (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count<BISHOP>(BLACK), 2)]);
   }
 
   // Compute the space weight
   if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)
   {
-      int minorPieceCount =  pos.piece_count(WHITE, KNIGHT) + pos.piece_count(WHITE, BISHOP)
-                           + pos.piece_count(BLACK, KNIGHT) + pos.piece_count(BLACK, BISHOP);
+      int minorPieceCount =  pos.count<KNIGHT>(WHITE) + pos.count<BISHOP>(WHITE)
+                           + pos.count<KNIGHT>(BLACK) + pos.count<BISHOP>(BLACK);
 
-      e->spaceWeight = minorPieceCount * minorPieceCount;
+      e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0);
   }
 
   // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder
   // for the bishop pair "extended piece", this allow us to be more flexible
   // in defining bishop pair bonuses.
   const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = {
-  { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(WHITE, PAWN), pos.piece_count(WHITE, KNIGHT),
-    pos.piece_count(WHITE, BISHOP)    , pos.piece_count(WHITE, ROOK), pos.piece_count(WHITE, QUEEN) },
-  { pos.piece_count(BLACK, BISHOP) > 1, pos.piece_count(BLACK, PAWN), pos.piece_count(BLACK, KNIGHT),
-    pos.piece_count(BLACK, BISHOP)    , pos.piece_count(BLACK, ROOK), pos.piece_count(BLACK, QUEEN) } };
+  { 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);
   return e;

src/material.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(MATERIAL_H_INCLUDED)
+#ifndef MATERIAL_H_INCLUDED
 #define MATERIAL_H_INCLUDED
 
 #include "endgame.h"
@@ -39,7 +39,7 @@ namespace Material {
 struct Entry {
 
   Score material_value() const { return make_score(value, value); }
-  int space_weight() const { return spaceWeight; }
+  Score space_weight() const { return spaceWeight; }
   Phase game_phase() const { return gamePhase; }
   bool specialized_eval_exists() const { return evaluationFunction != NULL; }
   Value evaluate(const Position& p) const { return (*evaluationFunction)(p); }
@@ -50,7 +50,7 @@ struct Entry {
   uint8_t factor[COLOR_NB];
   EndgameBase<Value>* evaluationFunction;
   EndgameBase<ScaleFactor>* scalingFunction[COLOR_NB];
-  int spaceWeight;
+  Score spaceWeight;
   Phase gamePhase;
 };
 
@@ -74,4 +74,4 @@ inline ScaleFactor Entry::scale_factor(const Position& pos, Color c) const {
 
 }
 
-#endif // !defined(MATERIAL_H_INCLUDED)
+#endif // #ifndef MATERIAL_H_INCLUDED

src/misc.cpp

@@ -24,17 +24,11 @@
 #include "misc.h"
 #include "thread.h"
 
-#if defined(__hpux)
-#    include <sys/pstat.h>
-#endif
-
 using namespace std;
 
-/// Version number. If Version is left empty, then Tag plus current
-/// date, in the format DD-MM-YY, are used as a version number.
-
-static const string Version = "3";
-static const string Tag = "";
+/// Version number. If Version is left empty, then compile date, in the
+/// format DD-MM-YY, is shown in engine_info.
+static const string Version = "DD";
 
 
 /// engine_info() returns the full name of the current Stockfish version. This
@@ -45,43 +39,33 @@ static const string Tag = "";
 const string engine_info(bool to_uci) {
 
   const string months("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec");
-  const string cpu64(Is64Bit ? " 64bit" : "");
-  const string popcnt(HasPopCnt ? " SSE4.2" : "");
-
   string month, day, year;
   stringstream s, date(__DATE__); // From compiler, format is "Sep 21 2008"
 
-  s << "Stockfish " << Version;
+  s << "Stockfish " << Version << setfill('0');
 
   if (Version.empty())
   {
       date >> month >> day >> year;
-
-      s << Tag << string(Tag.empty() ? "" : " ") << setfill('0') << setw(2) << day
-        << "-" << setw(2) << (1 + months.find(month) / 4) << "-" << year.substr(2);
+      s << setw(2) << day << setw(2) << (1 + months.find(month) / 4) << year.substr(2);
   }
 
-  s << cpu64 << popcnt << (to_uci ? "\nid author ": " by ")
+  s << (Is64Bit ? " 64" : "")
+    << (HasPopCnt ? " SSE4.2" : "")
+    << (to_uci ? "\nid author ": " by ")
     << "Tord Romstad, Marco Costalba and Joona Kiiski";
 
   return s.str();
 }
 
 
-/// Convert system time to milliseconds. That's all we need.
-
-Time::point Time::now() {
-  sys_time_t t; system_time(&t); return time_to_msec(t);
-}
-
-
 /// Debug functions used mainly to collect run-time statistics
 
 static uint64_t hits[2], means[2];
 
-void dbg_hit_on(bool b) { hits[0]++; if (b) hits[1]++; }
+void dbg_hit_on(bool b) { ++hits[0]; if (b) ++hits[1]; }
 void dbg_hit_on_c(bool c, bool b) { if (c) dbg_hit_on(b); }
-void dbg_mean_of(int v) { means[0]++; means[1] += v; }
+void dbg_mean_of(int v) { ++means[0]; means[1] += v; }
 
 void dbg_print() {
 
@@ -91,7 +75,7 @@ void dbg_print() {
 
   if (means[0])
       cerr << "Total " << means[0] << " Mean "
-           << (float)means[1] / means[0] << endl;
+           << (double)means[1] / means[0] << endl;
 }
 
 
@@ -174,37 +158,12 @@ std::ostream& operator<<(std::ostream& os, SyncCout sc) {
 void start_logger(bool b) { Logger::start(b); }
 
 
-/// cpu_count() tries to detect the number of CPU cores
-
-int cpu_count() {
-
-#if defined(_WIN32) || defined(_WIN64)
-  SYSTEM_INFO s;
-  GetSystemInfo(&s);
-  return s.dwNumberOfProcessors;
-#else
-
-#  if defined(_SC_NPROCESSORS_ONLN)
-  return sysconf(_SC_NPROCESSORS_ONLN);
-#  elif defined(__hpux)
-  struct pst_dynamic psd;
-  if (pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0) == -1)
-      return 1;
-  return psd.psd_proc_cnt;
-#  else
-  return 1;
-#  endif
-
-#endif
-}
-
-
 /// timed_wait() waits for msec milliseconds. It is mainly an helper to wrap
 /// conversion from milliseconds to struct timespec, as used by pthreads.
 
 void timed_wait(WaitCondition& sleepCond, Lock& sleepLock, int msec) {
 
-#if defined(_WIN32) || defined(_WIN64)
+#ifdef _WIN32
   int tm = msec;
 #else
   timespec ts, *tm = &ts;
@@ -221,7 +180,7 @@ void timed_wait(WaitCondition& sleepCond, Lock& sleepLock, int msec) {
 /// prefetch() preloads the given address in L1/L2 cache. This is a non
 /// blocking function and do not stalls the CPU waiting for data to be
 /// loaded from memory, that can be quite slow.
-#if defined(NO_PREFETCH)
+#ifdef NO_PREFETCH
 
 void prefetch(char*) {}
 
@@ -237,10 +196,8 @@ void prefetch(char* addr) {
 
 #  if defined(__INTEL_COMPILER) || defined(_MSC_VER)
   _mm_prefetch(addr, _MM_HINT_T0);
-  _mm_prefetch(addr+64, _MM_HINT_T0); // 64 bytes ahead
 #  else
   __builtin_prefetch(addr);
-  __builtin_prefetch(addr+64);
 #  endif
 }
 

src/misc.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(MISC_H_INCLUDED)
+#ifndef MISC_H_INCLUDED
 #define MISC_H_INCLUDED
 
 #include <fstream>
@@ -27,7 +27,6 @@
 #include "types.h"
 
 extern const std::string engine_info(bool to_uci = false);
-extern int cpu_count();
 extern void timed_wait(WaitCondition&, Lock&, int);
 extern void prefetch(char* addr);
 extern void start_logger(bool b);
@@ -46,7 +45,7 @@ struct Log : public std::ofstream {
 
 namespace Time {
   typedef int64_t point;
-  point now();
+  inline point now() { return system_time_to_msec(); }
 }
 
 
@@ -66,4 +65,4 @@ std::ostream& operator<<(std::ostream&, SyncCout);
 #define sync_cout std::cout << io_lock
 #define sync_endl std::endl << io_unlock
 
-#endif // !defined(MISC_H_INCLUDED)
+#endif // #ifndef MISC_H_INCLUDED

src/movegen.cpp

@@ -24,15 +24,15 @@
 
 /// Simple macro to wrap a very common while loop, no facny, no flexibility,
 /// hardcoded names 'mlist' and 'from'.
-#define SERIALIZE(b) while (b) (*mlist++).move = make_move(from, pop_lsb(&b))
+#define SERIALIZE(b) while (b) (mlist++)->move = make_move(from, pop_lsb(&b))
 
 /// Version used for pawns, where the 'from' square is given as a delta from the 'to' square
 #define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_lsb(&b); \
-                                         (*mlist++).move = make_move(to - (d), to); }
+                                         (mlist++)->move = make_move(to - (d), to); }
 namespace {
 
   template<CastlingSide Side, bool Checks, bool Chess960>
-  MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) {
+  ExtMove* generate_castle(const Position& pos, ExtMove* mlist, Color us) {
 
     if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side)))
         return mlist;
@@ -56,54 +56,42 @@ namespace {
     // 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 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies))
+    if (Chess960 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN)))
         return mlist;
 
-    (*mlist++).move = make<CASTLE>(kfrom, rfrom);
+    (mlist++)->move = make<CASTLE>(kfrom, rfrom);
 
-    if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos)))
-        mlist--;
+    if (Checks && !pos.gives_check((mlist - 1)->move, CheckInfo(pos)))
+        --mlist;
 
     return mlist;
   }
 
 
-  template<Square Delta>
-  inline Bitboard move_pawns(Bitboard p) {
-
-    return  Delta == DELTA_N  ?  p << 8
-          : Delta == DELTA_S  ?  p >> 8
-          : Delta == DELTA_NE ? (p & ~FileHBB) << 9
-          : Delta == DELTA_SE ? (p & ~FileHBB) >> 7
-          : Delta == DELTA_NW ? (p & ~FileABB) << 7
-          : Delta == DELTA_SW ? (p & ~FileABB) >> 9 : 0;
-  }
-
-
   template<GenType Type, Square Delta>
-  inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7,
-                                        Bitboard target, const CheckInfo* ci) {
+  inline ExtMove* generate_promotions(ExtMove* mlist, Bitboard pawnsOn7,
+                                      Bitboard target, const CheckInfo* ci) {
 
-    Bitboard b = move_pawns<Delta>(pawnsOn7) & target;
+    Bitboard b = shift_bb<Delta>(pawnsOn7) & target;
 
     while (b)
     {
         Square to = pop_lsb(&b);
 
         if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
-            (*mlist++).move = make<PROMOTION>(to - Delta, to, QUEEN);
+            (mlist++)->move = make<PROMOTION>(to - Delta, to, QUEEN);
 
         if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS)
         {
-            (*mlist++).move = make<PROMOTION>(to - Delta, to, ROOK);
-            (*mlist++).move = make<PROMOTION>(to - Delta, to, BISHOP);
-            (*mlist++).move = make<PROMOTION>(to - Delta, to, KNIGHT);
+            (mlist++)->move = make<PROMOTION>(to - Delta, to, ROOK);
+            (mlist++)->move = make<PROMOTION>(to - Delta, to, BISHOP);
+            (mlist++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
         }
 
         // Knight-promotion is the only one that can give a direct check not
         // already included in the queen-promotion.
         if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ci->ksq))
-            (*mlist++).move = make<PROMOTION>(to - Delta, to, KNIGHT);
+            (mlist++)->move = make<PROMOTION>(to - Delta, to, KNIGHT);
         else
             (void)ci; // Silence a warning under MSVC
     }
@@ -113,8 +101,8 @@ namespace {
 
 
   template<Color Us, GenType Type>
-  MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist,
-                                 Bitboard target, const CheckInfo* ci) {
+  ExtMove* generate_pawn_moves(const Position& pos, ExtMove* mlist,
+                               Bitboard target, const CheckInfo* ci) {
 
     // Compute our parametrized parameters at compile time, named according to
     // the point of view of white side.
@@ -122,9 +110,9 @@ namespace {
     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 ? DELTA_N  : DELTA_S);
-    const Square   RIGHT    = (Us == WHITE ? DELTA_NE : DELTA_SW);
-    const Square   LEFT     = (Us == WHITE ? DELTA_NW : DELTA_SE);
+    const Square   Up       = (Us == WHITE ? DELTA_N  : DELTA_S);
+    const Square   Right    = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Square   Left     = (Us == WHITE ? DELTA_NW : DELTA_SE);
 
     Bitboard b1, b2, dc1, dc2, emptySquares;
 
@@ -139,8 +127,8 @@ namespace {
     {
         emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces());
 
-        b1 = move_pawns<UP>(pawnsNotOn7)   & emptySquares;
-        b2 = move_pawns<UP>(b1 & TRank3BB) & emptySquares;
+        b1 = shift_bb<Up>(pawnsNotOn7)   & emptySquares;
+        b2 = shift_bb<Up>(b1 & TRank3BB) & emptySquares;
 
         if (Type == EVASIONS) // Consider only blocking squares
         {
@@ -159,16 +147,16 @@ namespace {
             // promotion has been already generated among captures.
             if (pawnsNotOn7 & ci->dcCandidates)
             {
-                dc1 = move_pawns<UP>(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq);
-                dc2 = move_pawns<UP>(dc1 & TRank3BB) & emptySquares;
+                dc1 = shift_bb<Up>(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq);
+                dc2 = shift_bb<Up>(dc1 & TRank3BB) & emptySquares;
 
                 b1 |= dc1;
                 b2 |= dc2;
             }
         }
 
-        SERIALIZE_PAWNS(b1, UP);
-        SERIALIZE_PAWNS(b2, UP + UP);
+        SERIALIZE_PAWNS(b1, Up);
+        SERIALIZE_PAWNS(b2, Up + Up);
     }
 
     // Promotions and underpromotions
@@ -180,19 +168,19 @@ namespace {
         if (Type == EVASIONS)
             emptySquares &= target;
 
-        mlist = generate_promotions<Type, RIGHT>(mlist, pawnsOn7, enemies, ci);
-        mlist = generate_promotions<Type, LEFT>(mlist, pawnsOn7, enemies, ci);
-        mlist = generate_promotions<Type, UP>(mlist, pawnsOn7, emptySquares, ci);
+        mlist = generate_promotions<Type, Right>(mlist, pawnsOn7, enemies, ci);
+        mlist = generate_promotions<Type, Left >(mlist, pawnsOn7, enemies, ci);
+        mlist = generate_promotions<Type, Up>(mlist, pawnsOn7, emptySquares, ci);
     }
 
     // Standard and en-passant captures
     if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS)
     {
-        b1 = move_pawns<RIGHT>(pawnsNotOn7) & enemies;
-        b2 = move_pawns<LEFT >(pawnsNotOn7) & enemies;
+        b1 = shift_bb<Right>(pawnsNotOn7) & enemies;
+        b2 = shift_bb<Left >(pawnsNotOn7) & enemies;
 
-        SERIALIZE_PAWNS(b1, RIGHT);
-        SERIALIZE_PAWNS(b2, LEFT);
+        SERIALIZE_PAWNS(b1, Right);
+        SERIALIZE_PAWNS(b2, Left);
 
         if (pos.ep_square() != SQ_NONE)
         {
@@ -201,7 +189,7 @@ namespace {
             // An en passant capture can be an evasion only if the checking piece
             // is the double pushed pawn and so is in the target. Otherwise this
             // is a discovery check and we are forced to do otherwise.
-            if (Type == EVASIONS && !(target & (pos.ep_square() - UP)))
+            if (Type == EVASIONS && !(target & (pos.ep_square() - Up)))
                 return mlist;
 
             b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
@@ -209,7 +197,7 @@ namespace {
             assert(b1);
 
             while (b1)
-                (*mlist++).move = make<ENPASSANT>(pop_lsb(&b1), pos.ep_square());
+                (mlist++)->move = make<ENPASSANT>(pop_lsb(&b1), pos.ep_square());
         }
     }
 
@@ -218,12 +206,12 @@ namespace {
 
 
   template<PieceType Pt, bool Checks> FORCE_INLINE
-  MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us,
-                            Bitboard target, const CheckInfo* ci) {
+  ExtMove* generate_moves(const Position& pos, ExtMove* mlist, Color us,
+                          Bitboard target, const CheckInfo* ci) {
 
     assert(Pt != KING && Pt != PAWN);
 
-    const Square* pl = pos.piece_list(us, Pt);
+    const Square* pl = pos.list<Pt>(us);
 
     for (Square from = *pl; from != SQ_NONE; from = *++pl)
     {
@@ -233,7 +221,7 @@ namespace {
                 && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt]))
                 continue;
 
-            if (ci->dcCandidates && (ci->dcCandidates & from))
+            if (unlikely(ci->dcCandidates) && (ci->dcCandidates & from))
                 continue;
         }
 
@@ -249,38 +237,36 @@ namespace {
   }
 
 
-  template<GenType Type> FORCE_INLINE
-  MoveStack* generate_all(const Position& pos, MoveStack* mlist, Color us,
-                          Bitboard target, const CheckInfo* ci = NULL) {
+  template<Color Us, GenType Type> FORCE_INLINE
+  ExtMove* generate_all(const Position& pos, ExtMove* mlist, Bitboard target,
+                        const CheckInfo* ci = NULL) {
 
     const bool Checks = Type == QUIET_CHECKS;
 
-    mlist = (us == WHITE ? generate_pawn_moves<WHITE, Type>(pos, mlist, target, ci)
-                         : generate_pawn_moves<BLACK, Type>(pos, mlist, target, ci));
-
-    mlist = generate_moves<KNIGHT, Checks>(pos, mlist, us, target, ci);
-    mlist = generate_moves<BISHOP, Checks>(pos, mlist, us, target, ci);
-    mlist = generate_moves<ROOK,   Checks>(pos, mlist, us, target, ci);
-    mlist = generate_moves<QUEEN,  Checks>(pos, mlist, us, target, ci);
+    mlist = generate_pawn_moves<Us, Type>(pos, mlist, target, ci);
+    mlist = generate_moves<KNIGHT, Checks>(pos, mlist, Us, target, ci);
+    mlist = generate_moves<BISHOP, Checks>(pos, mlist, Us, target, ci);
+    mlist = generate_moves<  ROOK, Checks>(pos, mlist, Us, target, ci);
+    mlist = generate_moves< QUEEN, Checks>(pos, mlist, Us, target, ci);
 
     if (Type != QUIET_CHECKS && Type != EVASIONS)
     {
-        Square from = pos.king_square(us);
+        Square from = pos.king_square(Us);
         Bitboard b = pos.attacks_from<KING>(from) & target;
         SERIALIZE(b);
     }
 
-    if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us))
+    if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(Us))
     {
         if (pos.is_chess960())
         {
-            mlist = generate_castle<KING_SIDE,  Checks, true>(pos, mlist, us);
-            mlist = generate_castle<QUEEN_SIDE, Checks, true>(pos, mlist, us);
+            mlist = generate_castle< KING_SIDE, Checks, true>(pos, mlist, Us);
+            mlist = generate_castle<QUEEN_SIDE, Checks, true>(pos, mlist, Us);
         }
         else
         {
-            mlist = generate_castle<KING_SIDE,  Checks, false>(pos, mlist, us);
-            mlist = generate_castle<QUEEN_SIDE, Checks, false>(pos, mlist, us);
+            mlist = generate_castle< KING_SIDE, Checks, false>(pos, mlist, Us);
+            mlist = generate_castle<QUEEN_SIDE, Checks, false>(pos, mlist, Us);
         }
     }
 
@@ -301,7 +287,7 @@ namespace {
 /// non-captures. Returns a pointer to the end of the move list.
 
 template<GenType Type>
-MoveStack* generate(const Position& pos, MoveStack* mlist) {
+ExtMove* generate(const Position& pos, ExtMove* mlist) {
 
   assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS);
   assert(!pos.checkers());
@@ -312,22 +298,24 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) {
                   : Type == QUIETS       ? ~pos.pieces()
                   : Type == NON_EVASIONS ? ~pos.pieces(us) : 0;
 
-  return generate_all<Type>(pos, mlist, us, target);
+  return us == WHITE ? generate_all<WHITE, Type>(pos, mlist, target)
+                     : generate_all<BLACK, Type>(pos, mlist, target);
 }
 
 // Explicit template instantiations
-template MoveStack* generate<CAPTURES>(const Position&, MoveStack*);
-template MoveStack* generate<QUIETS>(const Position&, MoveStack*);
-template MoveStack* generate<NON_EVASIONS>(const Position&, MoveStack*);
+template ExtMove* generate<CAPTURES>(const Position&, ExtMove*);
+template ExtMove* generate<QUIETS>(const Position&, ExtMove*);
+template ExtMove* generate<NON_EVASIONS>(const Position&, ExtMove*);
 
 
 /// generate<QUIET_CHECKS> generates all pseudo-legal non-captures and knight
 /// underpromotions that give check. Returns a pointer to the end of the move list.
 template<>
-MoveStack* generate<QUIET_CHECKS>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<QUIET_CHECKS>(const Position& pos, ExtMove* mlist) {
 
   assert(!pos.checkers());
 
+  Color us = pos.side_to_move();
   CheckInfo ci(pos);
   Bitboard dc = ci.dcCandidates;
 
@@ -347,21 +335,21 @@ MoveStack* generate<QUIET_CHECKS>(const Position& pos, MoveStack* mlist) {
      SERIALIZE(b);
   }
 
-  return generate_all<QUIET_CHECKS>(pos, mlist, pos.side_to_move(), ~pos.pieces(), &ci);
+  return us == WHITE ? generate_all<WHITE, QUIET_CHECKS>(pos, mlist, ~pos.pieces(), &ci)
+                     : generate_all<BLACK, QUIET_CHECKS>(pos, mlist, ~pos.pieces(), &ci);
 }
 
 
 /// generate<EVASIONS> generates all pseudo-legal check evasions when the side
 /// to move is in check. Returns a pointer to the end of the move list.
 template<>
-MoveStack* generate<EVASIONS>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<EVASIONS>(const Position& pos, ExtMove* mlist) {
 
   assert(pos.checkers());
 
-  Square from, checksq;
   int checkersCnt = 0;
   Color us = pos.side_to_move();
-  Square ksq = pos.king_square(us);
+  Square ksq = pos.king_square(us), from = ksq /* For SERIALIZE */, checksq;
   Bitboard sliderAttacks = 0;
   Bitboard b = pos.checkers();
 
@@ -371,65 +359,48 @@ MoveStack* generate<EVASIONS>(const Position& pos, MoveStack* mlist) {
   // evasions so to skip known illegal moves avoiding useless legality check later.
   do
   {
-      checkersCnt++;
+      ++checkersCnt;
       checksq = pop_lsb(&b);
 
       assert(color_of(pos.piece_on(checksq)) == ~us);
 
-      switch (type_of(pos.piece_on(checksq)))
-      {
-      case BISHOP: sliderAttacks |= PseudoAttacks[BISHOP][checksq]; break;
-      case ROOK:   sliderAttacks |= PseudoAttacks[ROOK][checksq];   break;
-      case QUEEN:
-          // If queen and king are far or not on a diagonal line we can safely
-          // remove all the squares attacked in the other direction becuase are
-          // not reachable by the king anyway.
-          if (between_bb(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq))
-              sliderAttacks |= PseudoAttacks[QUEEN][checksq];
+      if (type_of(pos.piece_on(checksq)) > KNIGHT) // A slider
+          sliderAttacks |= LineBB[checksq][ksq] ^ checksq;
 
-          // Otherwise we need to use real rook attacks to check if king is safe
-          // to move in the other direction. For example: king in B2, queen in A1
-          // a knight in B1, and we can safely move to C1.
-          else
-              sliderAttacks |= PseudoAttacks[BISHOP][checksq] | pos.attacks_from<ROOK>(checksq);
-
-      default:
-          break;
-      }
   } while (b);
 
   // Generate evasions for king, capture and non capture moves
   b = pos.attacks_from<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;
-  from = ksq;
   SERIALIZE(b);
 
   if (checkersCnt > 1)
       return mlist; // Double check, only a king move can save the day
 
   // Generate blocking evasions or captures of the checking piece
-  Bitboard target = between_bb(checksq, ksq) | pos.checkers();
+  Bitboard target = between_bb(checksq, ksq) | checksq;
 
-  return generate_all<EVASIONS>(pos, mlist, us, target);
+  return us == WHITE ? generate_all<WHITE, EVASIONS>(pos, mlist, target)
+                     : generate_all<BLACK, EVASIONS>(pos, mlist, target);
 }
 
 
 /// generate<LEGAL> generates all the legal moves in the given position
 
 template<>
-MoveStack* generate<LEGAL>(const Position& pos, MoveStack* mlist) {
+ExtMove* generate<LEGAL>(const Position& pos, ExtMove* mlist) {
 
-  MoveStack *end, *cur = mlist;
-  Bitboard pinned = pos.pinned_pieces();
+  ExtMove *end, *cur = mlist;
+  Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
   Square ksq = pos.king_square(pos.side_to_move());
 
   end = pos.checkers() ? generate<EVASIONS>(pos, mlist)
                        : generate<NON_EVASIONS>(pos, mlist);
   while (cur != end)
       if (   (pinned || from_sq(cur->move) == ksq || type_of(cur->move) == ENPASSANT)
-          && !pos.pl_move_is_legal(cur->move, pinned))
+          && !pos.legal(cur->move, pinned))
           cur->move = (--end)->move;
       else
-          cur++;
+          ++cur;
 
   return end;
 }

src/movegen.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(MOVEGEN_H_INCLUDED)
+#ifndef MOVEGEN_H_INCLUDED
 #define MOVEGEN_H_INCLUDED
 
 #include "types.h"
@@ -34,26 +34,25 @@ enum GenType {
 class Position;
 
 template<GenType>
-MoveStack* generate(const Position& pos, MoveStack* mlist);
+ExtMove* generate(const Position& pos, ExtMove* mlist);
 
 /// The MoveList struct is a simple wrapper around generate(), sometimes comes
 /// handy to use this class instead of the low level generate() function.
 template<GenType T>
 struct MoveList {
 
-  explicit MoveList(const Position& pos) : cur(mlist), last(generate<T>(pos, mlist)) {}
-  void operator++() { cur++; }
-  bool end() const { return cur == last; }
-  Move move() const { return cur->move; }
+  explicit MoveList(const Position& pos) : cur(mlist), last(generate<T>(pos, mlist)) { last->move = MOVE_NONE; }
+  void operator++() { ++cur; }
+  Move operator*() const { return cur->move; }
   size_t size() const { return last - mlist; }
   bool contains(Move m) const {
-    for (const MoveStack* it(mlist); it != last; ++it) if (it->move == m) return true;
+    for (const ExtMove* it(mlist); it != last; ++it) if (it->move == m) return true;
     return false;
   }
 
 private:
-  MoveStack mlist[MAX_MOVES];
-  MoveStack *cur, *last;
+  ExtMove mlist[MAX_MOVES];
+  ExtMove *cur, *last;
 };
 
-#endif // !defined(MOVEGEN_H_INCLUDED)
+#endif // #ifndef MOVEGEN_H_INCLUDED

src/movepick.cpp

@@ -25,7 +25,7 @@
 
 namespace {
 
-  enum Sequencer {
+  enum Stages {
     MAIN_SEARCH, CAPTURES_S1, KILLERS_S1, QUIETS_1_S1, QUIETS_2_S1, BAD_CAPTURES_S1,
     EVASION,     EVASIONS_S2,
     QSEARCH_0,   CAPTURES_S3, QUIET_CHECKS_S3,
@@ -36,9 +36,9 @@ namespace {
   };
 
   // Our insertion sort, guaranteed to be stable, as is needed
-  void insertion_sort(MoveStack* begin, MoveStack* end)
+  void insertion_sort(ExtMove* begin, ExtMove* end)
   {
-    MoveStack tmp, *p, *q;
+    ExtMove tmp, *p, *q;
 
     for (p = begin + 1; p < end; ++p)
     {
@@ -51,12 +51,12 @@ namespace {
 
   // Unary predicate used by std::partition to split positive scores from remaining
   // ones so to sort separately the two sets, and with the second sort delayed.
-  inline bool has_positive_score(const MoveStack& ms) { return ms.score > 0; }
+  inline bool has_positive_score(const ExtMove& ms) { return ms.score > 0; }
 
   // Picks and moves to the front the best move in the range [begin, end),
   // it is faster than sorting all the moves in advance when moves are few, as
   // normally are the possible captures.
-  inline MoveStack* pick_best(MoveStack* begin, MoveStack* end)
+  inline ExtMove* pick_best(ExtMove* begin, ExtMove* end)
   {
       std::swap(*begin, *std::max_element(begin, end));
       return begin;
@@ -70,83 +70,70 @@ namespace {
 /// search captures, promotions and some checks) and about how important good
 /// move ordering is at the current node.
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
-                       Search::Stack* s, Value beta) : pos(p), Hist(h), depth(d) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
+                       Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) {
 
   assert(d > DEPTH_ZERO);
 
-  captureThreshold = 0;
   cur = end = moves;
   endBadCaptures = moves + MAX_MOVES - 1;
+  countermoves = cm;
   ss = s;
 
   if (p.checkers())
-      phase = EVASION;
+      stage = EVASION;
 
   else
-  {
-      phase = MAIN_SEARCH;
+      stage = MAIN_SEARCH;
 
-      killers[0].move = ss->killers[0];
-      killers[1].move = ss->killers[1];
-
-      // Consider sligtly negative captures as good if at low depth and far from beta
-      if (ss && ss->staticEval < beta - PawnValueMg && d < 3 * ONE_PLY)
-          captureThreshold = -PawnValueMg;
-
-      // Consider negative captures as good if still enough to reach beta
-      else if (ss && ss->staticEval > beta)
-          captureThreshold = beta - ss->staticEval;
-  }
-
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
   end += (ttMove != MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
-                       Square sq) : pos(p), Hist(h), cur(moves), end(moves) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
+                       Square sq) : pos(p), history(h), cur(moves), end(moves) {
 
   assert(d <= DEPTH_ZERO);
 
   if (p.checkers())
-      phase = EVASION;
+      stage = EVASION;
 
   else if (d > DEPTH_QS_NO_CHECKS)
-      phase = QSEARCH_0;
+      stage = QSEARCH_0;
 
   else if (d > DEPTH_QS_RECAPTURES)
   {
-      phase = QSEARCH_1;
+      stage = QSEARCH_1;
 
       // Skip TT move if is not a capture or a promotion, this avoids qsearch
       // tree explosion due to a possible perpetual check or similar rare cases
       // when TT table is full.
-      if (ttm && !pos.is_capture_or_promotion(ttm))
+      if (ttm && !pos.capture_or_promotion(ttm))
           ttm = MOVE_NONE;
   }
   else
   {
-      phase = RECAPTURE;
+      stage = RECAPTURE;
       recaptureSquare = sq;
       ttm = MOVE_NONE;
   }
 
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
   end += (ttMove != MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType pt)
-                       : pos(p), Hist(h), cur(moves), end(moves) {
+MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, PieceType pt)
+                       : pos(p), history(h), cur(moves), end(moves) {
 
   assert(!pos.checkers());
 
-  phase = PROBCUT;
+  stage = PROBCUT;
 
   // In ProbCut we generate only captures better than parent's captured piece
   captureThreshold = PieceValue[MG][pt];
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
 
-  if (ttMove && (!pos.is_capture(ttMove) ||  pos.see(ttMove) <= captureThreshold))
+  if (ttMove && (!pos.capture(ttMove) || pos.see(ttMove) <= captureThreshold))
       ttMove = MOVE_NONE;
 
   end += (ttMove != MOVE_NONE);
@@ -172,11 +159,11 @@ void MovePicker::score<CAPTURES>() {
   // some SEE calls in case we get a cutoff (idea from Pablo Vazquez).
   Move m;
 
-  for (MoveStack* it = moves; it != end; ++it)
+  for (ExtMove* it = moves; it != end; ++it)
   {
       m = it->move;
       it->score =  PieceValue[MG][pos.piece_on(to_sq(m))]
-                 - type_of(pos.piece_moved(m));
+                 - type_of(pos.moved_piece(m));
 
       if (type_of(m) == PROMOTION)
           it->score += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
@@ -191,10 +178,10 @@ void MovePicker::score<QUIETS>() {
 
   Move m;
 
-  for (MoveStack* it = moves; it != end; ++it)
+  for (ExtMove* it = moves; it != end; ++it)
   {
       m = it->move;
-      it->score = Hist[pos.piece_moved(m)][to_sq(m)];
+      it->score = history[pos.moved_piece(m)][to_sq(m)];
   }
 }
 
@@ -206,17 +193,17 @@ void MovePicker::score<EVASIONS>() {
   Move m;
   int seeScore;
 
-  for (MoveStack* it = moves; it != end; ++it)
+  for (ExtMove* it = moves; it != end; ++it)
   {
       m = it->move;
       if ((seeScore = pos.see_sign(m)) < 0)
-          it->score = seeScore - History::Max; // At the bottom
+          it->score = seeScore - HistoryStats::Max; // At the bottom
 
-      else if (pos.is_capture(m))
+      else if (pos.capture(m))
           it->score =  PieceValue[MG][pos.piece_on(to_sq(m))]
-                     - type_of(pos.piece_moved(m)) + History::Max;
+                     - type_of(pos.moved_piece(m)) + HistoryStats::Max;
       else
-          it->score = Hist[pos.piece_moved(m)][to_sq(m)];
+          it->score = history[pos.moved_piece(m)][to_sq(m)];
   }
 }
 
@@ -228,7 +215,7 @@ void MovePicker::generate_next() {
 
   cur = moves;
 
-  switch (++phase) {
+  switch (++stage) {
 
   case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6:
       end = generate<CAPTURES>(pos, moves);
@@ -238,6 +225,19 @@ void MovePicker::generate_next() {
   case KILLERS_S1:
       cur = killers;
       end = cur + 2;
+
+      killers[0].move = ss->killers[0];
+      killers[1].move = ss->killers[1];
+      killers[2].move = killers[3].move = MOVE_NONE;
+
+      // Be sure countermoves are different from killers
+      for (int i = 0; i < 2; ++i)
+          if (countermoves[i] != cur->move && countermoves[i] != (cur+1)->move)
+              (end++)->move = countermoves[i];
+
+      if (countermoves[1] && countermoves[1] == countermoves[0]) // Due to SMP races
+          killers[3].move = MOVE_NONE;
+
       return;
 
   case QUIETS_1_S1:
@@ -271,7 +271,7 @@ void MovePicker::generate_next() {
       return;
 
   case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE:
-      phase = STOP;
+      stage = STOP;
   case STOP:
       end = cur + 1; // Avoid another next_phase() call
       return;
@@ -296,19 +296,17 @@ Move MovePicker::next_move<false>() {
       while (cur == end)
           generate_next();
 
-      switch (phase) {
+      switch (stage) {
 
       case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT:
-          cur++;
+          ++cur;
           return ttMove;
 
       case CAPTURES_S1:
           move = pick_best(cur++, end)->move;
           if (move != ttMove)
           {
-              assert(captureThreshold <= 0); // Otherwise we cannot use see_sign()
-
-              if (pos.see_sign(move) >= captureThreshold)
+              if (pos.see_sign(move) >= 0)
                   return move;
 
               // Losing capture, move it to the tail of the array
@@ -319,9 +317,9 @@ Move MovePicker::next_move<false>() {
       case KILLERS_S1:
           move = (cur++)->move;
           if (    move != MOVE_NONE
-              &&  pos.is_pseudo_legal(move)
+              &&  pos.pseudo_legal(move)
               &&  move != ttMove
-              && !pos.is_capture(move))
+              && !pos.capture(move))
               return move;
           break;
 
@@ -329,7 +327,9 @@ Move MovePicker::next_move<false>() {
           move = (cur++)->move;
           if (   move != ttMove
               && move != killers[0].move
-              && move != killers[1].move)
+              && move != killers[1].move
+              && move != killers[2].move
+              && move != killers[3].move)
               return move;
           break;
 

src/movepick.h

@@ -17,11 +17,11 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined MOVEPICK_H_INCLUDED
+#ifndef MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 
 #include <algorithm> // For std::max
-#include <cstring>   // For memset
+#include <cstring>   // For std::memset
 
 #include "movegen.h"
 #include "position.h"
@@ -30,20 +30,29 @@
 
 
 /// The Stats struct stores moves statistics. According to the template parameter
-/// the class can store both History and Gains type statistics. History records
-/// how often different moves have been successful or unsuccessful during the
-/// current search and is used for reduction and move ordering decisions. Gains
-/// records the move's best evaluation gain from one ply to the next and is used
-/// for pruning decisions. Entries are stored according only to moving piece and
-/// destination square, in particular two moves with different origin but same
-/// destination and same piece will be considered identical.
-template<bool Gain>
+/// the class can store History, Gains 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. Gains records the move's
+/// best evaluation gain from one ply to the next and is used for pruning decisions.
+/// Countermoves store the move that refute a previous one. Entries are stored
+/// according only to moving piece and destination square, hence two moves with
+/// different origin but same destination and piece will be considered identical.
+template<bool Gain, typename T>
 struct Stats {
 
   static const Value Max = Value(2000);
 
-  const Value* operator[](Piece p) const { return &table[p][0]; }
-  void clear() { memset(table, 0, sizeof(table)); }
+  const T* operator[](Piece p) const { return table[p]; }
+  void clear() { std::memset(table, 0, sizeof(table)); }
+
+  void update(Piece p, Square to, Move m) {
+
+    if (m == table[p][to].first)
+        return;
+
+    table[p][to].second = table[p][to].first;
+    table[p][to].first = m;
+  }
 
   void update(Piece p, Square to, Value v) {
 
@@ -55,11 +64,12 @@ struct Stats {
   }
 
 private:
-  Value table[PIECE_NB][SQUARE_NB];
+  T table[PIECE_NB][SQUARE_NB];
 };
 
-typedef Stats<false> History;
-typedef Stats<true> Gains;
+typedef Stats< true, Value> GainsStats;
+typedef Stats<false, Value> HistoryStats;
+typedef Stats<false, std::pair<Move, Move> > CountermovesStats;
 
 
 /// MovePicker class is used to pick one pseudo legal move at a time from the
@@ -74,9 +84,10 @@ class MovePicker {
   MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
 
 public:
-  MovePicker(const Position&, Move, Depth, const History&, Search::Stack*, Value);
-  MovePicker(const Position&, Move, Depth, const History&, Square);
-  MovePicker(const Position&, Move, const History&, PieceType);
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
+  MovePicker(const Position&, Move, const HistoryStats&, PieceType);
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*);
+
   template<bool SpNode> Move next_move();
 
 private:
@@ -84,15 +95,16 @@ private:
   void generate_next();
 
   const Position& pos;
-  const History& Hist;
+  const HistoryStats& history;
   Search::Stack* ss;
+  Move* countermoves;
   Depth depth;
   Move ttMove;
-  MoveStack killers[2];
+  ExtMove killers[4];
   Square recaptureSquare;
-  int captureThreshold, phase;
-  MoveStack *cur, *end, *endQuiets, *endBadCaptures;
-  MoveStack moves[MAX_MOVES];
+  int captureThreshold, stage;
+  ExtMove *cur, *end, *endQuiets, *endBadCaptures;
+  ExtMove moves[MAX_MOVES];
 };
 
-#endif // !defined(MOVEPICK_H_INCLUDED)
+#endif // #ifndef MOVEPICK_H_INCLUDED

src/notation.cpp

@@ -89,9 +89,9 @@ Move move_from_uci(const Position& pos, string& str) {
   if (str.length() == 5) // Junior could send promotion piece in uppercase
       str[4] = char(tolower(str[4]));
 
-  for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
-      if (str == move_to_uci(ml.move(), pos.is_chess960()))
-          return ml.move();
+  for (MoveList<LEGAL> it(pos); *it; ++it)
+      if (str == move_to_uci(*it, pos.is_chess960()))
+          return *it;
 
   return MOVE_NONE;
 }
@@ -133,7 +133,7 @@ const string move_to_san(Position& pos, Move m) {
           while (b)
           {
               Move move = make_move(pop_lsb(&b), to);
-              if (!pos.pl_move_is_legal(move, pos.pinned_pieces()))
+              if (!pos.legal(move, pos.pinned_pieces(pos.side_to_move())))
                   others ^= from_sq(move);
           }
 
@@ -149,10 +149,10 @@ const string move_to_san(Position& pos, Move m) {
                   san += square_to_string(from);
           }
       }
-      else if (pos.is_capture(m))
+      else if (pos.capture(m))
           san = file_to_char(file_of(from));
 
-      if (pos.is_capture(m))
+      if (pos.capture(m))
           san += 'x';
 
       san += square_to_string(to);
@@ -161,7 +161,7 @@ const string move_to_san(Position& pos, Move m) {
           san += string("=") + PieceToChar[WHITE][promotion_type(m)];
   }
 
-  if (pos.move_gives_check(m, CheckInfo(pos)))
+  if (pos.gives_check(m, CheckInfo(pos)))
   {
       StateInfo st;
       pos.do_move(m, st);
@@ -207,7 +207,7 @@ static string score_to_string(Value v) {
       s << "-#" << (VALUE_MATE + v) / 2;
 
   else
-      s << setprecision(2) << fixed << showpos << float(v) / PawnValueMg;
+      s << setprecision(2) << fixed << showpos << double(v) / PawnValueMg;
 
   return s.str();
 }

src/notation.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(NOTATION_H_INCLUDED)
+#ifndef NOTATION_H_INCLUDED
 #define NOTATION_H_INCLUDED
 
 #include <string>
@@ -32,4 +32,4 @@ const std::string move_to_uci(Move m, bool chess960);
 const std::string move_to_san(Position& pos, Move m);
 std::string pretty_pv(Position& pos, int depth, Value score, int64_t msecs, Move pv[]);
 
-#endif // !defined(NOTATION_H_INCLUDED)
+#endif // #ifndef NOTATION_H_INCLUDED

src/pawns.cpp

@@ -17,6 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <algorithm>
 #include <cassert>
 
 #include "bitboard.h"
@@ -29,71 +30,75 @@ namespace {
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
 
-  // Doubled pawn penalty by opposed flag and file
-  const Score DoubledPawnPenalty[2][FILE_NB] = {
-  { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
-    S(23, 48), S(23, 48), S(20, 48), S(13, 43) },
-  { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
-    S(23, 48), S(23, 48), S(20, 48), S(13, 43) }};
+  // Doubled pawn penalty by file
+  const Score Doubled[FILE_NB] = {
+    S(13, 43), S(20, 48), S(23, 48), S(23, 48),
+    S(23, 48), S(23, 48), S(20, 48), S(13, 43) };
 
   // Isolated pawn penalty by opposed flag and file
-  const Score IsolatedPawnPenalty[2][FILE_NB] = {
+  const Score Isolated[2][FILE_NB] = {
   { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
     S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
   { S(25, 30), S(36, 35), S(40, 35), S(40, 35),
-    S(40, 35), S(40, 35), S(36, 35), S(25, 30) }};
+    S(40, 35), S(40, 35), S(36, 35), S(25, 30) } };
 
   // Backward pawn penalty by opposed flag and file
-  const Score BackwardPawnPenalty[2][FILE_NB] = {
+  const Score Backward[2][FILE_NB] = {
   { S(30, 42), S(43, 46), S(49, 46), S(49, 46),
     S(49, 46), S(49, 46), S(43, 46), S(30, 42) },
   { S(20, 28), S(29, 31), S(33, 31), S(33, 31),
-    S(33, 31), S(33, 31), S(29, 31), S(20, 28) }};
+    S(33, 31), S(33, 31), S(29, 31), S(20, 28) } };
 
-  // Pawn chain membership bonus by file
-  const Score ChainBonus[FILE_NB] = {
-    S(11,-1), S(13,-1), S(13,-1), S(14,-1),
-    S(14,-1), S(13,-1), S(13,-1), S(11,-1)
-  };
+  // Pawn chain membership bonus by file and rank (initialized by formula)
+  Score ChainMember[FILE_NB][RANK_NB];
 
   // Candidate passed pawn bonus by rank
-  const Score CandidateBonus[RANK_NB] = {
+  const Score CandidatePassed[RANK_NB] = {
     S( 0, 0), S( 6, 13), S(6,13), S(14,29),
-    S(34,68), S(83,166), S(0, 0), S( 0, 0)
-  };
+    S(34,68), S(83,166), S(0, 0), S( 0, 0) };
 
-  const Score PawnStructureWeight = S(233, 201);
+  // Weakness of our pawn shelter in front of the king indexed by [rank]
+  const Value ShelterWeakness[RANK_NB] =
+  { V(100), V(0), V(27), V(73), V(92), V(101), V(101) };
 
-  // Weakness of our pawn shelter in front of the king indexed by [king pawn][rank]
-  const Value ShelterWeakness[2][RANK_NB] =
-  { { V(141), V(0), V(38), V(102), V(128), V(141), V(141) },
-    { V( 61), V(0), V(16), V( 44), V( 56), V( 61), V( 61) } };
-
-  // Danger of enemy pawns moving toward our king indexed by [pawn blocked][rank]
-  const Value StormDanger[2][RANK_NB] =
-  { { V(26), V(0), V(128), V(51), V(26) },
-    { V(13), V(0), V( 64), V(25), V(13) } };
+  // Danger of enemy pawns moving toward our king indexed by
+  // [no friendly pawn | pawn unblocked | pawn blocked][rank of enemy pawn]
+  const Value StormDanger[3][RANK_NB] = {
+  { V( 0),  V(64), V(128), V(51), V(26) },
+  { V(26),  V(32), V( 96), V(38), V(20) },
+  { V( 0),  V( 0), V( 64), V(25), V(13) } };
 
   // Max bonus for king safety. Corresponds to start position with all the pawns
-  // in front of the king and no enemy pawn on the horizont.
+  // in front of the king and no enemy pawn on the horizon.
   const Value MaxSafetyBonus = V(263);
 
   #undef S
   #undef V
 
   template<Color Us>
-  Score evaluate_pawns(const Position& pos, Bitboard ourPawns,
-                       Bitboard theirPawns, Pawns::Entry* e) {
+  Score evaluate(const Position& pos, Pawns::Entry* e) {
 
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    const Color  Them  = (Us == WHITE ? BLACK    : WHITE);
+    const Square Up    = (Us == WHITE ? DELTA_N  : DELTA_S);
+    const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Square Left  = (Us == WHITE ? DELTA_NW : DELTA_SE);
 
     Bitboard b;
     Square s;
     File f;
-    Rank r;
     bool passed, isolated, doubled, opposed, chain, backward, candidate;
     Score value = SCORE_ZERO;
-    const Square* pl = pos.piece_list(Us, PAWN);
+    const Square* pl = pos.list<PAWN>(Us);
+
+    Bitboard ourPawns = pos.pieces(Us, PAWN);
+    Bitboard theirPawns = pos.pieces(Them, PAWN);
+
+    e->passedPawns[Us] = e->candidatePawns[Us] = 0;
+    e->kingSquares[Us] = SQ_NONE;
+    e->semiopenFiles[Us] = 0xFF;
+    e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
+    e->pawnsOnSquares[Us][BLACK] = popcount<Max15>(ourPawns & DarkSquares);
+    e->pawnsOnSquares[Us][WHITE] = pos.count<PAWN>(Us) - e->pawnsOnSquares[Us][BLACK];
 
     // Loop through all pawns of the current color and score each pawn
     while ((s = *pl++) != SQ_NONE)
@@ -101,13 +106,12 @@ namespace {
         assert(pos.piece_on(s) == make_piece(Us, PAWN));
 
         f = file_of(s);
-        r = rank_of(s);
 
-        // This file cannot be half open
-        e->halfOpenFiles[Us] &= ~(1 << f);
+        // This file cannot be semi-open
+        e->semiopenFiles[Us] &= ~(1 << f);
 
         // Our rank plus previous one. Used for chain detection
-        b = rank_bb(r) | rank_bb(Us == WHITE ? r - Rank(1) : r + Rank(1));
+        b = rank_bb(s) | rank_bb(s - pawn_push(Us));
 
         // Flag the pawn as passed, isolated, doubled or member of a pawn
         // chain (but not the backward one).
@@ -117,41 +121,37 @@ namespace {
         opposed  =   theirPawns & forward_bb(Us, s);
         passed   = !(theirPawns & passed_pawn_mask(Us, s));
 
-        // Test for backward pawn
-        backward = false;
-
+        // Test for backward pawn.
         // If the pawn is passed, isolated, or member of a pawn chain it cannot
         // be backward. If there are friendly pawns behind on adjacent files
         // or if can capture an enemy pawn it cannot be backward either.
-        if (   !(passed | isolated | chain)
-            && !(ourPawns & attack_span_mask(Them, s))
-            && !(pos.attacks_from<PAWN>(s, Us) & theirPawns))
+        if (   (passed | isolated | chain)
+            || (ourPawns & pawn_attack_span(Them, s))
+            || (pos.attacks_from<PAWN>(s, Us) & theirPawns))
+            backward = false;
+        else
         {
             // We now know that there are no friendly pawns beside or behind this
             // pawn on adjacent files. We now check whether the pawn is
             // backward by looking in the forward direction on the adjacent
-            // files, and seeing whether we meet a friendly or an enemy pawn first.
-            b = pos.attacks_from<PAWN>(s, Us);
+            // files, and picking the closest pawn there.
+            b = pawn_attack_span(Us, s) & (ourPawns | theirPawns);
+            b = pawn_attack_span(Us, s) & rank_bb(backmost_sq(Us, b));
 
-            // Note that we are sure to find something because pawn is not passed
-            // nor isolated, so loop is potentially infinite, but it isn't.
-            while (!(b & (ourPawns | theirPawns)))
-                Us == WHITE ? b <<= 8 : b >>= 8;
-
-            // The friendly pawn needs to be at least two ranks closer than the
-            // enemy pawn in order to help the potentially backward pawn advance.
-            backward = (b | (Us == WHITE ? b << 8 : b >> 8)) & theirPawns;
+            // If we have an enemy pawn in the same or next rank, the pawn is
+            // backward because it cannot advance without being captured.
+            backward = (b | shift_bb<Up>(b)) & theirPawns;
         }
 
-        assert(opposed | passed | (attack_span_mask(Us, s) & theirPawns));
+        assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
 
-        // A not passed pawn is a candidate to become passed if it is free to
+        // A not passed pawn is a candidate to become passed, if it is free to
         // advance and if the number of friendly pawns beside or behind this
         // pawn on adjacent files is higher or equal than the number of
         // enemy pawns in the forward direction on the adjacent files.
         candidate =   !(opposed | passed | backward | isolated)
-                   && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != 0
-                   &&  popcount<Max15>(b) >= popcount<Max15>(attack_span_mask(Us, s) & theirPawns);
+                   && (b = pawn_attack_span(Them, s + pawn_push(Us)) & ourPawns) != 0
+                   &&  popcount<Max15>(b) >= popcount<Max15>(pawn_attack_span(Us, s) & theirPawns);
 
         // Passed pawns will be properly scored in evaluation because we need
         // full attack info to evaluate passed pawns. Only the frontmost passed
@@ -161,33 +161,49 @@ namespace {
 
         // Score this pawn
         if (isolated)
-            value -= IsolatedPawnPenalty[opposed][f];
+            value -= Isolated[opposed][f];
 
         if (doubled)
-            value -= DoubledPawnPenalty[opposed][f];
+            value -= Doubled[f];
 
         if (backward)
-            value -= BackwardPawnPenalty[opposed][f];
+            value -= Backward[opposed][f];
 
         if (chain)
-            value += ChainBonus[f];
+            value += ChainMember[f][relative_rank(Us, s)];
 
         if (candidate)
-            value += CandidateBonus[relative_rank(Us, s)];
+        {
+            value += CandidatePassed[relative_rank(Us, s)];
+
+            if (!doubled)
+                e->candidatePawns[Us] |= s;
+        }
     }
 
-    e->pawnsOnSquares[Us][BLACK] = popcount<Max15>(ourPawns & BlackSquares);
-    e->pawnsOnSquares[Us][WHITE] = pos.piece_count(Us, PAWN) - e->pawnsOnSquares[Us][BLACK];
-
-    e->pawnsOnSquares[Them][BLACK] = popcount<Max15>(theirPawns & BlackSquares);
-    e->pawnsOnSquares[Them][WHITE] = pos.piece_count(Them, PAWN) - e->pawnsOnSquares[Them][BLACK];
-
     return value;
   }
-}
+
+} // namespace
 
 namespace Pawns {
 
+/// init() initializes some tables by formula instead of hard-code their values
+
+void init() {
+
+  const int chainByFile[8] = { 1, 3, 3, 4, 4, 3, 3, 1 };
+  int bonus;
+
+  for (Rank r = RANK_1; r < RANK_8; ++r)
+      for (File f = FILE_A; f <= FILE_H; ++f)
+      {
+          bonus = r * (r-1) * (r-2) + chainByFile[f] * (r/2 + 1);
+          ChainMember[f][r] = make_score(bonus, bonus);
+      }
+}
+
+
 /// probe() takes a position object as input, computes a Entry object, and returns
 /// a pointer to it. The result is also stored in a hash table, so we don't have
 /// to recompute everything when the same pawn structure occurs again.
@@ -197,27 +213,11 @@ Entry* probe(const Position& pos, Table& entries) {
   Key key = pos.pawn_key();
   Entry* e = entries[key];
 
-  // If e->key matches the position's pawn hash key, it means that we
-  // have analysed this pawn structure before, and we can simply return
-  // the information we found the last time instead of recomputing it.
   if (e->key == key)
       return e;
 
   e->key = key;
-  e->passedPawns[WHITE] = e->passedPawns[BLACK] = 0;
-  e->kingSquares[WHITE] = e->kingSquares[BLACK] = SQ_NONE;
-  e->halfOpenFiles[WHITE] = e->halfOpenFiles[BLACK] = 0xFF;
-
-  Bitboard wPawns = pos.pieces(WHITE, PAWN);
-  Bitboard bPawns = pos.pieces(BLACK, PAWN);
-  e->pawnAttacks[WHITE] = ((wPawns & ~FileHBB) << 9) | ((wPawns & ~FileABB) << 7);
-  e->pawnAttacks[BLACK] = ((bPawns & ~FileHBB) >> 7) | ((bPawns & ~FileABB) >> 9);
-
-  e->value =  evaluate_pawns<WHITE>(pos, wPawns, bPawns, e)
-            - evaluate_pawns<BLACK>(pos, bPawns, wPawns, e);
-
-  e->value = apply_weight(e->value, PawnStructureWeight);
-
+  e->value = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
   return e;
 }
 
@@ -231,25 +231,21 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
   const Color Them = (Us == WHITE ? BLACK : WHITE);
 
   Value safety = MaxSafetyBonus;
-  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, ksq) | rank_bb(ksq));
-  Bitboard ourPawns = b & pos.pieces(Us) & ~rank_bb(ksq);
+  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq));
+  Bitboard ourPawns = b & pos.pieces(Us);
   Bitboard theirPawns = b & pos.pieces(Them);
   Rank rkUs, rkThem;
-  File kf = file_of(ksq);
+  File kf = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
 
-  kf = (kf == FILE_A) ? FILE_B : (kf == FILE_H) ? FILE_G : kf;
-
-  for (int f = kf - 1; f <= kf + 1; f++)
+  for (File f = kf - File(1); f <= kf + File(1); ++f)
   {
-      // Shelter penalty is higher for the pawn in front of the king
-      b = ourPawns & FileBB[f];
-      rkUs = b ? rank_of(Us == WHITE ? lsb(b) : ~msb(b)) : RANK_1;
-      safety -= ShelterWeakness[f != kf][rkUs];
+      b = ourPawns & file_bb(f);
+      rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+      safety -= ShelterWeakness[rkUs];
 
-      // Storm danger is smaller if enemy pawn is blocked
-      b  = theirPawns & FileBB[f];
-      rkThem = b ? rank_of(Us == WHITE ? lsb(b) : ~msb(b)) : RANK_1;
-      safety -= StormDanger[rkThem == rkUs + 1][rkThem];
+      b  = theirPawns & file_bb(f);
+      rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      safety -= StormDanger[rkUs == RANK_1 ? 0 : rkThem == rkUs + 1 ? 2 : 1][rkThem];
   }
 
   return safety;
@@ -275,7 +271,7 @@ Score Entry::update_safety(const Position& pos, Square ksq) {
 
   Value bonus = shelter_storm<Us>(pos, ksq);
 
-  // If we can castle use the bonus after the castle if is bigger
+  // If we can castle use the bonus after the castle if it is bigger
   if (pos.can_castle(make_castle_right(Us, KING_SIDE)))
       bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
 

src/pawns.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(PAWNS_H_INCLUDED)
+#ifndef PAWNS_H_INCLUDED
 #define PAWNS_H_INCLUDED
 
 #include "misc.h"
@@ -37,10 +37,13 @@ struct Entry {
   Score pawns_value() const { return value; }
   Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
   Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
-  int file_is_half_open(Color c, File f) const { return halfOpenFiles[c] & (1 << int(f)); }
-  int has_open_file_to_left(Color c, File f) const { return halfOpenFiles[c] & ((1 << int(f)) - 1); }
-  int has_open_file_to_right(Color c, File f) const { return halfOpenFiles[c] & ~((1 << int(f+1)) - 1); }
-  int pawns_on_same_color_squares(Color c, Square s) const { return pawnsOnSquares[c][!!(BlackSquares & s)]; }
+  Bitboard candidate_pawns(Color c) const { return candidatePawns[c]; }
+  int pawns_on_same_color_squares(Color c, Square s) const { return pawnsOnSquares[c][!!(DarkSquares & s)]; }
+  int semiopen(Color c, File f) const { return semiopenFiles[c] & (1 << int(f)); }
+  int semiopen_on_side(Color c, File f, bool left) const {
+
+    return semiopenFiles[c] & (left ? ((1 << int(f)) - 1) : ~((1 << int(f+1)) - 1));
+  }
 
   template<Color Us>
   Score king_safety(const Position& pos, Square ksq)  {
@@ -57,20 +60,22 @@ struct Entry {
 
   Key key;
   Bitboard passedPawns[COLOR_NB];
+  Bitboard candidatePawns[COLOR_NB];
   Bitboard pawnAttacks[COLOR_NB];
   Square kingSquares[COLOR_NB];
   int minKPdistance[COLOR_NB];
   int castleRights[COLOR_NB];
   Score value;
-  int halfOpenFiles[COLOR_NB];
+  int semiopenFiles[COLOR_NB];
   Score kingSafety[COLOR_NB];
   int pawnsOnSquares[COLOR_NB][COLOR_NB];
 };
 
 typedef HashTable<Entry, 16384> Table;
 
+void init();
 Entry* probe(const Position& pos, Table& entries);
 
 }
 
-#endif // !defined(PAWNS_H_INCLUDED)
+#endif // #ifndef PAWNS_H_INCLUDED

src/platform.h

@@ -17,10 +17,10 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(PLATFORM_H_INCLUDED)
+#ifndef PLATFORM_H_INCLUDED
 #define PLATFORM_H_INCLUDED
 
-#if defined(_MSC_VER)
+#ifdef _MSC_VER
 
 // Disable some silly and noisy warning from MSVC compiler
 #pragma warning(disable: 4127) // Conditional expression is constant
@@ -40,16 +40,17 @@ typedef unsigned __int64 uint64_t;
 
 #else
 #  include <inttypes.h>
-#  include <unistd.h>  // Used by sysconf(_SC_NPROCESSORS_ONLN)
 #endif
 
-#if !defined(_WIN32) && !defined(_WIN64) // Linux - Unix
+#ifndef _WIN32 // Linux - Unix
 
 #  include <sys/time.h>
-typedef timeval sys_time_t;
 
-inline void system_time(sys_time_t* t) { gettimeofday(t, NULL); }
-inline int64_t time_to_msec(const sys_time_t& t) { return t.tv_sec * 1000LL + t.tv_usec / 1000; }
+inline int64_t system_time_to_msec() {
+  timeval t;
+  gettimeofday(&t, NULL);
+  return t.tv_sec * 1000LL + t.tv_usec / 1000;
+}
 
 #  include <pthread.h>
 typedef pthread_mutex_t Lock;
@@ -66,18 +67,20 @@ typedef void*(*pt_start_fn)(void*);
 #  define cond_signal(x) pthread_cond_signal(&(x))
 #  define cond_wait(x,y) pthread_cond_wait(&(x),&(y))
 #  define cond_timedwait(x,y,z) pthread_cond_timedwait(&(x),&(y),z)
-#  define thread_create(x,f,t) !pthread_create(&(x),NULL,(pt_start_fn)f,t)
+#  define thread_create(x,f,t) pthread_create(&(x),NULL,(pt_start_fn)f,t)
 #  define thread_join(x) pthread_join(x, NULL)
 
 #else // Windows and MinGW
 
 #  include <sys/timeb.h>
-typedef _timeb sys_time_t;
 
-inline void system_time(sys_time_t* t) { _ftime(t); }
-inline int64_t time_to_msec(const sys_time_t& t) { return t.time * 1000LL + t.millitm; }
+inline int64_t system_time_to_msec() {
+  _timeb t;
+  _ftime(&t);
+  return t.time * 1000LL + t.millitm;
+}
 
-#if !defined(NOMINMAX)
+#ifndef NOMINMAX
 #  define NOMINMAX // disable macros min() and max()
 #endif
 
@@ -105,9 +108,9 @@ inline DWORD* dwWin9xKludge() { static DWORD dw; return &dw; }
 #  define cond_signal(x) SetEvent(x)
 #  define cond_wait(x,y) { lock_release(y); WaitForSingleObject(x, INFINITE); lock_grab(y); }
 #  define cond_timedwait(x,y,z) { lock_release(y); WaitForSingleObject(x,z); lock_grab(y); }
-#  define thread_create(x,f,t) (x = CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)f,t,0,dwWin9xKludge()), x != NULL)
+#  define thread_create(x,f,t) (x = CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)f,t,0,dwWin9xKludge()))
 #  define thread_join(x) { WaitForSingleObject(x, INFINITE); CloseHandle(x); }
 
 #endif
 
-#endif // !defined(PLATFORM_H_INCLUDED)
+#endif // #ifndef PLATFORM_H_INCLUDED

src/position.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(POSITION_H_INCLUDED)
+#ifndef POSITION_H_INCLUDED
 #define POSITION_H_INCLUDED
 
 #include <cassert>
@@ -43,16 +43,16 @@ struct CheckInfo {
 };
 
 
-/// The StateInfo struct stores information we need to restore a Position
+/// The StateInfo struct stores information needed to restore a Position
 /// object to its previous state when we retract a move. Whenever a move
-/// is made on the board (by calling Position::do_move), a StateInfo object
-/// must be passed as a parameter.
+/// is made on the board (by calling Position::do_move), a StateInfo
+/// object must be passed as a parameter.
 
 struct StateInfo {
   Key pawnKey, materialKey;
   Value npMaterial[COLOR_NB];
   int castleRights, rule50, pliesFromNull;
-  Score psqScore;
+  Score psq;
   Square epSquare;
 
   Key key;
@@ -67,27 +67,10 @@ struct StateInfo {
 const size_t StateCopySize64 = offsetof(StateInfo, key) / sizeof(uint64_t) + 1;
 
 
-/// The position data structure. A position consists of the following data:
-///
-///    * For each piece type, a bitboard representing the squares occupied
-///      by pieces of that type.
-///    * For each color, a bitboard representing the squares occupied by
-///      pieces of that color.
-///    * A bitboard of all occupied squares.
-///    * A bitboard of all checking pieces.
-///    * A 64-entry array of pieces, indexed by the squares of the board.
-///    * The current side to move.
-///    * Information about the castling rights for both sides.
-///    * The initial files of the kings and both pairs of rooks. This is
-///      used to implement the Chess960 castling rules.
-///    * The en passant square (which is SQ_NONE if no en passant capture is
-///      possible).
-///    * The squares of the kings for both sides.
-///    * Hash keys for the position itself, the current pawn structure, and
-///      the current material situation.
-///    * Hash keys for all previous positions in the game for detecting
-///      repetition draws.
-///    * A counter for detecting 50 move rule draws.
+/// The Position class stores the information regarding the board representation
+/// like pieces, side to move, hash keys, castling info, etc. The most important
+/// methods are do_move() and undo_move(), used by the search to update node info
+/// when traversing the search tree.
 
 class Position {
 public:
@@ -95,6 +78,7 @@ public:
   Position(const Position& p, Thread* t) { *this = p; thisThread = t; }
   Position(const std::string& f, bool c960, Thread* t) { set(f, c960, t); }
   Position& operator=(const Position&);
+  static void init();
 
   // Text input/output
   void set(const std::string& fen, bool isChess960, Thread* th);
@@ -111,9 +95,9 @@ public:
   Piece piece_on(Square s) const;
   Square king_square(Color c) const;
   Square ep_square() const;
-  bool is_empty(Square s) const;
-  const Square* piece_list(Color c, PieceType pt) const;
-  int piece_count(Color c, PieceType pt) const;
+  bool empty(Square s) const;
+  template<PieceType Pt> int count(Color c) const;
+  template<PieceType Pt> const Square* list(Color c) const;
 
   // Castling
   int can_castle(CastleRight f) const;
@@ -124,7 +108,7 @@ public:
   // Checking
   Bitboard checkers() const;
   Bitboard discovered_check_candidates() const;
-  Bitboard pinned_pieces() const;
+  Bitboard pinned_pieces(Color toMove) const;
 
   // Attacks to/from a given square
   Bitboard attackers_to(Square s) const;
@@ -135,20 +119,20 @@ public:
   template<PieceType> Bitboard attacks_from(Square s, Color c) const;
 
   // Properties of moves
-  bool move_gives_check(Move m, const CheckInfo& ci) const;
-  bool pl_move_is_legal(Move m, Bitboard pinned) const;
-  bool is_pseudo_legal(const Move m) const;
-  bool is_capture(Move m) const;
-  bool is_capture_or_promotion(Move m) const;
-  bool is_passed_pawn_push(Move m) const;
-  Piece piece_moved(Move m) const;
+  bool legal(Move m, Bitboard pinned) const;
+  bool pseudo_legal(const Move m) const;
+  bool capture(Move m) const;
+  bool capture_or_promotion(Move m) const;
+  bool gives_check(Move m, const CheckInfo& ci) const;
+  bool passed_pawn_push(Move m) const;
+  Piece moved_piece(Move m) const;
   PieceType captured_piece_type() const;
 
   // Piece specific
-  bool pawn_is_passed(Color c, Square s) const;
+  bool pawn_passed(Color c, Square s) const;
   bool pawn_on_7th(Color c) const;
-  bool opposite_bishops() const;
   bool bishop_pair(Color c) const;
+  bool opposite_bishops() const;
 
   // Doing and undoing moves
   void do_move(Move m, StateInfo& st);
@@ -169,7 +153,6 @@ public:
 
   // Incremental piece-square evaluation
   Score psq_score() const;
-  Score psq_delta(Piece p, Square from, Square to) const;
   Value non_pawn_material(Color c) const;
 
   // Other properties of the position
@@ -188,12 +171,14 @@ public:
 private:
   // Initialization helpers (used while setting up a position)
   void clear();
-  void put_piece(Piece p, Square s);
   void set_castle_right(Color c, Square rfrom);
 
   // Helper functions
   void do_castle(Square kfrom, Square kto, Square rfrom, Square rto);
-  template<bool FindPinned> Bitboard hidden_checkers() const;
+  Bitboard hidden_checkers(Square ksq, Color c, Color toMove) const;
+  void put_piece(Square s, Color c, PieceType pt);
+  void remove_piece(Square s, Color c, PieceType pt);
+  void move_piece(Square from, Square to, Color c, PieceType pt);
 
   // Computing hash keys from scratch (for initialization and debugging)
   Key compute_key() const;
@@ -237,11 +222,11 @@ inline Piece Position::piece_on(Square s) const {
   return board[s];
 }
 
-inline Piece Position::piece_moved(Move m) const {
+inline Piece Position::moved_piece(Move m) const {
   return board[from_sq(m)];
 }
 
-inline bool Position::is_empty(Square s) const {
+inline bool Position::empty(Square s) const {
   return board[s] == NO_PIECE;
 }
 
@@ -273,12 +258,12 @@ inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const {
   return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]);
 }
 
-inline int Position::piece_count(Color c, PieceType pt) const {
-  return pieceCount[c][pt];
+template<PieceType Pt> inline int Position::count(Color c) const {
+  return pieceCount[c][Pt];
 }
 
-inline const Square* Position::piece_list(Color c, PieceType pt) const {
-  return pieceList[c][pt];
+template<PieceType Pt> inline const Square* Position::list(Color c) const {
+  return pieceList[c][Pt];
 }
 
 inline Square Position::ep_square() const {
@@ -331,25 +316,27 @@ inline Bitboard Position::checkers() const {
 }
 
 inline Bitboard Position::discovered_check_candidates() const {
-  return hidden_checkers<false>();
+  return hidden_checkers(king_square(~sideToMove), sideToMove, sideToMove);
 }
 
-inline Bitboard Position::pinned_pieces() const {
-  return hidden_checkers<true>();
+inline Bitboard Position::pinned_pieces(Color toMove) const {
+  return hidden_checkers(king_square(toMove), ~toMove, toMove);
 }
 
-inline bool Position::pawn_is_passed(Color c, Square s) const {
+inline bool Position::pawn_passed(Color c, Square s) const {
   return !(pieces(~c, PAWN) & passed_pawn_mask(c, s));
 }
 
+inline bool Position::passed_pawn_push(Move m) const {
+
+  return   type_of(moved_piece(m)) == PAWN
+        && pawn_passed(sideToMove, to_sq(m));
+}
+
 inline Key Position::key() const {
   return st->key;
 }
 
-inline Key Position::exclusion_key() const {
-  return st->key ^ Zobrist::exclusion;
-}
-
 inline Key Position::pawn_key() const {
   return st->pawnKey;
 }
@@ -358,24 +345,14 @@ inline Key Position::material_key() const {
   return st->materialKey;
 }
 
-inline Score Position::psq_delta(Piece p, Square from, Square to) const {
-  return pieceSquareTable[p][to] - pieceSquareTable[p][from];
-}
-
 inline Score Position::psq_score() const {
-  return st->psqScore;
+  return st->psq;
 }
 
 inline Value Position::non_pawn_material(Color c) const {
   return st->npMaterial[c];
 }
 
-inline bool Position::is_passed_pawn_push(Move m) const {
-
-  return   type_of(piece_moved(m)) == PAWN
-        && pawn_is_passed(sideToMove, to_sq(m));
-}
-
 inline int Position::game_ply() const {
   return gamePly;
 }
@@ -401,17 +378,17 @@ inline bool Position::is_chess960() const {
   return chess960;
 }
 
-inline bool Position::is_capture_or_promotion(Move m) const {
+inline bool Position::capture_or_promotion(Move m) const {
 
   assert(is_ok(m));
-  return type_of(m) ? type_of(m) != CASTLE : !is_empty(to_sq(m));
+  return type_of(m) ? type_of(m) != CASTLE : !empty(to_sq(m));
 }
 
-inline bool Position::is_capture(Move m) const {
+inline bool Position::capture(Move m) const {
 
   // Note that castle is coded as "king captures the rook"
   assert(is_ok(m));
-  return (!is_empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT;
+  return (!empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT;
 }
 
 inline PieceType Position::captured_piece_type() const {
@@ -422,4 +399,46 @@ inline Thread* Position::this_thread() const {
   return thisThread;
 }
 
-#endif // !defined(POSITION_H_INCLUDED)
+inline void Position::put_piece(Square s, Color c, PieceType pt) {
+
+  board[s] = make_piece(c, pt);
+  byTypeBB[ALL_PIECES] |= s;
+  byTypeBB[pt] |= s;
+  byColorBB[c] |= s;
+  pieceCount[c][ALL_PIECES]++;
+  index[s] = pieceCount[c][pt]++;
+  pieceList[c][pt][index[s]] = s;
+}
+
+inline void Position::move_piece(Square from, Square to, Color c, PieceType pt) {
+
+  // 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[pt] ^= from_to_bb;
+  byColorBB[c] ^= from_to_bb;
+  board[from] = NO_PIECE;
+  board[to] = make_piece(c, pt);
+  index[to] = index[from];
+  pieceList[c][pt][index[to]] = to;
+}
+
+inline void Position::remove_piece(Square s, Color c, PieceType pt) {
+
+  // WARNING: This is not a reversible operation. If we remove a piece in
+  // do_move() and then replace it in undo_move() we will put it at the end of
+  // the list and not in its original place, it means index[] and pieceList[]
+  // are not guaranteed to be invariant to a do_move() + undo_move() sequence.
+  byTypeBB[ALL_PIECES] ^= s;
+  byTypeBB[pt] ^= s;
+  byColorBB[c] ^= s;
+  /* board[s] = NO_PIECE; */ // Not needed, will be overwritten by capturing
+  pieceCount[c][ALL_PIECES]--;
+  Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]];
+  index[lastSquare] = index[s];
+  pieceList[c][pt][index[lastSquare]] = lastSquare;
+  pieceList[c][pt][pieceCount[c][pt]] = SQ_NONE;
+}
+
+#endif // #ifndef POSITION_H_INCLUDED

src/psqtab.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(PSQTAB_H_INCLUDED)
+#ifndef PSQTAB_H_INCLUDED
 #define PSQTAB_H_INCLUDED
 
 #include "types.h"
@@ -33,12 +33,12 @@ static const Score PSQT[][SQUARE_NB] = {
   { },
   { // Pawn
    S(  0, 0), S( 0, 0), S( 0, 0), S( 0, 0), S(0,  0), S( 0, 0), S( 0, 0), S(  0, 0),
-   S(-28,-8), S(-6,-8), S( 4,-8), S(14,-8), S(14,-8), S( 4,-8), S(-6,-8), S(-28,-8),
-   S(-28,-8), S(-6,-8), S( 9,-8), S(36,-8), S(36,-8), S( 9,-8), S(-6,-8), S(-28,-8),
-   S(-28,-8), S(-6,-8), S(17,-8), S(58,-8), S(58,-8), S(17,-8), S(-6,-8), S(-28,-8),
-   S(-28,-8), S(-6,-8), S(17,-8), S(36,-8), S(36,-8), S(17,-8), S(-6,-8), S(-28,-8),
-   S(-28,-8), S(-6,-8), S( 9,-8), S(14,-8), S(14,-8), S( 9,-8), S(-6,-8), S(-28,-8),
-   S(-28,-8), S(-6,-8), S( 4,-8), S(14,-8), S(14,-8), S( 4,-8), S(-6,-8), S(-28,-8),
+   S(-20,-8), S(-6,-8), S( 4,-8), S(14,-8), S(14,-8), S( 4,-8), S(-6,-8), S(-20,-8),
+   S(-20,-8), S(-6,-8), S( 9,-8), S(34,-8), S(34,-8), S( 9,-8), S(-6,-8), S(-20,-8),
+   S(-20,-8), S(-6,-8), S(17,-8), S(54,-8), S(54,-8), S(17,-8), S(-6,-8), S(-20,-8),
+   S(-20,-8), S(-6,-8), S(17,-8), S(34,-8), S(34,-8), S(17,-8), S(-6,-8), S(-20,-8),
+   S(-20,-8), S(-6,-8), S( 9,-8), S(14,-8), S(14,-8), S( 9,-8), S(-6,-8), S(-20,-8),
+   S(-20,-8), S(-6,-8), S( 4,-8), S(14,-8), S(14,-8), S( 4,-8), S(-6,-8), S(-20,-8),
    S(  0, 0), S( 0, 0), S( 0, 0), S( 0, 0), S(0,  0), S( 0, 0), S( 0, 0), S(  0, 0)
   },
   { // Knight
@@ -95,4 +95,4 @@ static const Score PSQT[][SQUARE_NB] = {
 
 #undef S
 
-#endif // !defined(PSQTAB_H_INCLUDED)
+#endif // #ifndef PSQTAB_H_INCLUDED

src/rkiss.h

@@ -22,7 +22,7 @@
   (at your option) any later version.
 */
 
-#if !defined(RKISS_H_INCLUDED)
+#ifndef RKISS_H_INCLUDED
 #define RKISS_H_INCLUDED
 
 #include "types.h"
@@ -43,34 +43,31 @@
 
 class RKISS {
 
-  // Keep variables always together
-  struct S { uint64_t a, b, c, d; } s;
+  uint64_t a, b, c, d;
 
   uint64_t rotate(uint64_t x, uint64_t k) const {
     return (x << k) | (x >> (64 - k));
   }
 
-  // Return 64 bit unsigned integer in between [0, 2^64 - 1]
   uint64_t rand64() {
 
-    const uint64_t
-      e = s.a - rotate(s.b,  7);
-    s.a = s.b ^ rotate(s.c, 13);
-    s.b = s.c + rotate(s.d, 37);
-    s.c = s.d + e;
-    return s.d = e + s.a;
+    const uint64_t e = a - rotate(b,  7);
+    a = b ^ rotate(c, 13);
+    b = c + rotate(d, 37);
+    c = d + e;
+    return d = e + a;
   }
 
 public:
   RKISS(int seed = 73) {
 
-    s.a = 0xf1ea5eed;
-    s.b = s.c = s.d = 0xd4e12c77;
-    for (int i = 0; i < seed; i++) // Scramble a few rounds
+    a = 0xF1EA5EED, b = c = d = 0xD4E12C77;
+
+    for (int i = 0; i < seed; ++i) // Scramble a few rounds
         rand64();
   }
 
   template<typename T> T rand() { return T(rand64()); }
 };
 
-#endif // !defined(RKISS_H_INCLUDED)
+#endif // #ifndef RKISS_H_INCLUDED

src/search.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(SEARCH_H_INCLUDED)
+#ifndef SEARCH_H_INCLUDED
 #define SEARCH_H_INCLUDED
 
 #include <cstring>
@@ -45,9 +45,7 @@ struct Stack {
   Move killers[2];
   Depth reduction;
   Value staticEval;
-  Value evalMargin;
   int skipNullMove;
-  int futilityMoveCount;
 };
 
 
@@ -79,7 +77,7 @@ struct RootMove {
 
 struct LimitsType {
 
-  LimitsType() { memset(this, 0, sizeof(LimitsType)); }
+  LimitsType() { std::memset(this, 0, sizeof(LimitsType)); }
   bool use_time_management() const { return !(mate | movetime | depth | nodes | infinite); }
 
   int time[COLOR_NB], inc[COLOR_NB], movestogo, depth, nodes, movetime, mate, infinite, ponder;
@@ -109,4 +107,4 @@ extern void think();
 
 } // namespace Search
 
-#endif // !defined(SEARCH_H_INCLUDED)
+#endif // #ifndef SEARCH_H_INCLUDED

src/thread.cpp

@@ -19,7 +19,6 @@
 
 #include <algorithm> // For std::count
 #include <cassert>
-#include <iostream>
 
 #include "movegen.h"
 #include "search.h"
@@ -30,42 +29,64 @@ using namespace Search;
 
 ThreadPool Threads; // Global object
 
-namespace { extern "C" {
+namespace {
 
  // start_routine() is the C function which is called when a new thread
  // is launched. It is a wrapper to the virtual function idle_loop().
 
- long start_routine(Thread* th) { th->idle_loop(); return 0; }
-
-} }
+ extern "C" { long start_routine(ThreadBase* th) { th->idle_loop(); return 0; } }
 
 
-// Thread c'tor starts a newly-created thread of execution that will call
-// the the virtual function idle_loop(), going immediately to sleep.
+ // Helpers to launch a thread after creation and joining before delete. Must be
+ // outside Thread c'tor and d'tor because object shall be fully initialized
+ // when start_routine (and hence virtual idle_loop) is called and when joining.
+
+ template<typename T> T* new_thread() {
+   T* th = new T();
+   thread_create(th->handle, start_routine, th); // Will go to sleep
+   return th;
+ }
+
+ void delete_thread(ThreadBase* th) {
+   th->exit = true; // Search must be already finished
+   th->notify_one();
+   thread_join(th->handle); // Wait for thread termination
+   delete th;
+ }
+
+}
+
+
+// ThreadBase::notify_one() wakes up the thread when there is some work to do
+
+void ThreadBase::notify_one() {
+
+  mutex.lock();
+  sleepCondition.notify_one();
+  mutex.unlock();
+}
+
+
+// ThreadBase::wait_for() set the thread to sleep until condition 'b' turns true
+
+void ThreadBase::wait_for(volatile const bool& b) {
+
+  mutex.lock();
+  while (!b) sleepCondition.wait(mutex);
+  mutex.unlock();
+}
+
+
+// Thread c'tor just inits data but does not launch any thread of execution that
+// instead will be started only upon c'tor returns.
 
 Thread::Thread() /* : splitPoints() */ { // Value-initialization bug in MSVC
 
-  searching = exit = false;
+  searching = false;
   maxPly = splitPointsSize = 0;
   activeSplitPoint = NULL;
   activePosition = NULL;
   idx = Threads.size();
-
-  if (!thread_create(handle, start_routine, this))
-  {
-      std::cerr << "Failed to create thread number " << idx << std::endl;
-      ::exit(EXIT_FAILURE);
-  }
-}
-
-
-// Thread d'tor waits for thread termination before to return
-
-Thread::~Thread() {
-
-  exit = true; // Search must be already finished
-  notify_one();
-  thread_join(handle); // Wait for thread termination
 }
 
 
@@ -80,11 +101,11 @@ void TimerThread::idle_loop() {
       mutex.lock();
 
       if (!exit)
-          sleepCondition.wait_for(mutex, msec ? msec : INT_MAX);
+          sleepCondition.wait_for(mutex, run ? Resolution : INT_MAX);
 
       mutex.unlock();
 
-      if (msec)
+      if (run)
           check_time();
   }
 }
@@ -123,26 +144,6 @@ void MainThread::idle_loop() {
 }
 
 
-// Thread::notify_one() wakes up the thread when there is some search to do
-
-void Thread::notify_one() {
-
-  mutex.lock();
-  sleepCondition.notify_one();
-  mutex.unlock();
-}
-
-
-// Thread::wait_for() set the thread to sleep until condition 'b' turns true
-
-void Thread::wait_for(volatile const bool& b) {
-
-  mutex.lock();
-  while (!b) sleepCondition.wait(mutex);
-  mutex.unlock();
-}
-
-
 // Thread::cutoff_occurred() checks whether a beta cutoff has occurred in the
 // current active split point, or in some ancestor of the split point.
 
@@ -156,14 +157,14 @@ bool Thread::cutoff_occurred() const {
 }
 
 
-// Thread::is_available_to() checks whether the thread is available to help the
+// Thread::available_to() checks whether the thread is available to help the
 // thread 'master' at a split point. An obvious requirement is that thread must
 // be idle. With more than two threads, this is not sufficient: If the thread is
 // the master of some split point, it is only available as a slave to the slaves
 // which are busy searching the split point at the top of slaves split point
 // stack (the "helpful master concept" in YBWC terminology).
 
-bool Thread::is_available_to(Thread* master) const {
+bool Thread::available_to(const Thread* master) const {
 
   if (searching)
       return false;
@@ -186,8 +187,8 @@ bool Thread::is_available_to(Thread* master) const {
 void ThreadPool::init() {
 
   sleepWhileIdle = true;
-  timer = new TimerThread();
-  push_back(new MainThread());
+  timer = new_thread<TimerThread>();
+  push_back(new_thread<MainThread>());
   read_uci_options();
 }
 
@@ -196,10 +197,10 @@ void ThreadPool::init() {
 
 void ThreadPool::exit() {
 
-  delete timer; // As first because check_time() accesses threads data
+  delete_thread(timer); // As first because check_time() accesses threads data
 
   for (iterator it = begin(); it != end(); ++it)
-      delete *it;
+      delete_thread(*it);
 }
 
 
@@ -216,12 +217,19 @@ void ThreadPool::read_uci_options() {
 
   assert(requested > 0);
 
+  // Value 0 has a special meaning: We determine the optimal minimum split depth
+  // automatically. Anyhow the minimumSplitDepth should never be under 4 plies.
+  if (!minimumSplitDepth)
+      minimumSplitDepth = (requested < 8 ? 4 : 7) * ONE_PLY;
+  else
+      minimumSplitDepth = std::max(4 * ONE_PLY, minimumSplitDepth);
+
   while (size() < requested)
-      push_back(new Thread());
+      push_back(new_thread<Thread>());
 
   while (size() > requested)
   {
-      delete back();
+      delete_thread(back());
       pop_back();
   }
 }
@@ -230,10 +238,10 @@ void ThreadPool::read_uci_options() {
 // slave_available() tries to find an idle thread which is available as a slave
 // for the thread 'master'.
 
-Thread* ThreadPool::available_slave(Thread* master) const {
+Thread* ThreadPool::available_slave(const Thread* master) const {
 
   for (const_iterator it = begin(); it != end(); ++it)
-      if ((*it)->is_available_to(master))
+      if ((*it)->available_to(master))
           return *it;
 
   return NULL;
@@ -250,9 +258,9 @@ Thread* ThreadPool::available_slave(Thread* master) const {
 // search() then split() returns.
 
 template <bool Fake>
-void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bestValue,
+void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Value* bestValue,
                    Move* bestMove, Depth depth, Move threatMove, int moveCount,
-                   MovePicker* movePicker, int nodeType) {
+                   MovePicker* movePicker, int nodeType, bool cutNode) {
 
   assert(pos.pos_is_ok());
   assert(*bestValue <= alpha && alpha < beta && beta <= VALUE_INFINITE);
@@ -274,6 +282,7 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   sp.alpha = alpha;
   sp.beta = beta;
   sp.nodeType = nodeType;
+  sp.cutNode = cutNode;
   sp.movePicker = movePicker;
   sp.moveCount = moveCount;
   sp.pos = &pos;
@@ -287,7 +296,7 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   Threads.mutex.lock();
   sp.mutex.lock();
 
-  splitPointsSize++;
+  ++splitPointsSize;
   activeSplitPoint = &sp;
   activePosition = NULL;
 
@@ -321,13 +330,13 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
 
       // We have returned from the idle loop, which means that all threads are
       // finished. Note that setting 'searching' and decreasing splitPointsSize is
-      // done under lock protection to avoid a race with Thread::is_available_to().
+      // done under lock protection to avoid a race with Thread::available_to().
       Threads.mutex.lock();
       sp.mutex.lock();
   }
 
   searching = true;
-  splitPointsSize--;
+  --splitPointsSize;
   activeSplitPoint = sp.parentSplitPoint;
   activePosition = &pos;
   pos.set_nodes_searched(pos.nodes_searched() + sp.nodes);
@@ -339,15 +348,15 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
 }
 
 // Explicit template instantiations
-template void Thread::split<false>(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int);
-template void Thread::split< true>(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int);
+template void Thread::split<false>(Position&, const Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool);
+template void Thread::split< true>(Position&, const Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool);
 
 
 // wait_for_think_finished() waits for main thread to go to sleep then returns
 
 void ThreadPool::wait_for_think_finished() {
 
-  MainThread* t = main_thread();
+  MainThread* t = main();
   t->mutex.lock();
   while (t->thinking) sleepCondition.wait(t->mutex);
   t->mutex.unlock();
@@ -366,16 +375,20 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
   Signals.stopOnPonderhit = Signals.firstRootMove = false;
   Signals.stop = Signals.failedLowAtRoot = false;
 
+  RootMoves.clear();
   RootPos = pos;
   Limits = limits;
-  SetupStates = states; // Ownership transfer here
-  RootMoves.clear();
+  if (states.get()) // If we don't set a new position, preserve current state
+  {
+      SetupStates = states; // Ownership transfer here
+      assert(!states.get());
+  }
 
-  for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
+  for (MoveList<LEGAL> it(pos); *it; ++it)
       if (   searchMoves.empty()
-          || std::count(searchMoves.begin(), searchMoves.end(), ml.move()))
-          RootMoves.push_back(RootMove(ml.move()));
+          || std::count(searchMoves.begin(), searchMoves.end(), *it))
+          RootMoves.push_back(RootMove(*it));
 
-  main_thread()->thinking = true;
-  main_thread()->notify_one(); // Starts main thread
+  main()->thinking = true;
+  main()->notify_one(); // Starts main thread
 }

src/thread.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(THREAD_H_INCLUDED)
+#ifndef THREAD_H_INCLUDED
 #define THREAD_H_INCLUDED
 
 #include <vector>
@@ -68,6 +68,7 @@ struct SplitPoint {
   Value beta;
   int nodeType;
   Move threatMove;
+  bool cutNode;
 
   // Const pointers to shared data
   MovePicker* movePicker;
@@ -85,25 +86,39 @@ struct SplitPoint {
 };
 
 
+/// ThreadBase struct is the base of the hierarchy from where we derive all the
+/// specialized thread classes.
+
+struct ThreadBase {
+
+  ThreadBase() : exit(false) {}
+  virtual ~ThreadBase() {}
+  virtual void idle_loop() = 0;
+  void notify_one();
+  void wait_for(volatile const bool& b);
+
+  Mutex mutex;
+  ConditionVariable sleepCondition;
+  NativeHandle handle;
+  volatile bool exit;
+};
+
+
 /// Thread struct keeps together all the thread related stuff like locks, state
 /// and especially split points. 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.
 
-struct Thread {
+struct Thread : public ThreadBase {
 
   Thread();
-  virtual ~Thread();
-
   virtual void idle_loop();
-  void notify_one();
   bool cutoff_occurred() const;
-  bool is_available_to(Thread* master) const;
-  void wait_for(volatile const bool& b);
+  bool available_to(const Thread* master) const;
 
   template <bool Fake>
-  void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
-             Depth depth, Move threatMove, int moveCount, MovePicker* movePicker, int nodeType);
+  void split(Position& pos, const Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
+             Depth depth, Move threatMove, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode);
 
   SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD];
   Material::Table materialTable;
@@ -112,17 +127,13 @@ struct Thread {
   Position* activePosition;
   size_t idx;
   int maxPly;
-  Mutex mutex;
-  ConditionVariable sleepCondition;
-  NativeHandle handle;
   SplitPoint* volatile activeSplitPoint;
   volatile int splitPointsSize;
   volatile bool searching;
-  volatile bool exit;
 };
 
 
-/// MainThread and TimerThread are sublassed from Thread to characterize the two
+/// MainThread and TimerThread are derived classes used to characterize the two
 /// special threads: the main one and the recurring timer.
 
 struct MainThread : public Thread {
@@ -131,10 +142,11 @@ struct MainThread : public Thread {
   volatile bool thinking;
 };
 
-struct TimerThread : public Thread {
-  TimerThread() : msec(0) {}
+struct TimerThread : public ThreadBase {
+  TimerThread() : run(false) {}
   virtual void idle_loop();
-  int msec;
+  bool run;
+  static const int Resolution = 5; // msec between two check_time() calls
 };
 
 
@@ -147,9 +159,9 @@ struct ThreadPool : public std::vector<Thread*> {
   void init(); // No c'tor and d'tor, threads rely on globals that should
   void exit(); // be initialized and valid during the whole thread lifetime.
 
-  MainThread* main_thread() { return static_cast<MainThread*>((*this)[0]); }
+  MainThread* main() { return static_cast<MainThread*>((*this)[0]); }
   void read_uci_options();
-  Thread* available_slave(Thread* master) const;
+  Thread* available_slave(const Thread* master) const;
   void wait_for_think_finished();
   void start_thinking(const Position&, const Search::LimitsType&,
                       const std::vector<Move>&, Search::StateStackPtr&);
@@ -164,4 +176,4 @@ struct ThreadPool : public std::vector<Thread*> {
 
 extern ThreadPool Threads;
 
-#endif // !defined(THREAD_H_INCLUDED)
+#endif // #ifndef THREAD_H_INCLUDED

src/timeman.cpp

@@ -17,8 +17,8 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <cmath>
 #include <algorithm>
+#include <cmath>
 
 #include "search.h"
 #include "timeman.h"
@@ -29,8 +29,8 @@ namespace {
   /// Constants
 
   const int MoveHorizon  = 50;    // Plan time management at most this many moves ahead
-  const float MaxRatio   = 7.0f;  // When in trouble, we can step over reserved time with this ratio
-  const float StealRatio = 0.33f; // However we must not steal time from remaining moves over this ratio
+  const double MaxRatio   = 7.0;  // When in trouble, we can step over reserved time with this ratio
+  const double StealRatio = 0.33; // However we must not steal time from remaining moves over this ratio
 
 
   // MoveImportance[] is based on naive statistical analysis of "how many games are still undecided
@@ -76,10 +76,9 @@ namespace {
 }
 
 
-void TimeManager::pv_instability(int curChanges, int prevChanges) {
+void TimeManager::pv_instability(double bestMoveChanges) {
 
-  unstablePVExtraTime =  curChanges  * (optimumSearchTime / 2)
-                       + prevChanges * (optimumSearchTime / 3);
+  unstablePVExtraTime = int(bestMoveChanges * optimumSearchTime / 1.4);
 }
 
 
@@ -115,7 +114,7 @@ void TimeManager::init(const Search::LimitsType& limits, int currentPly, Color u
 
   // We calculate optimum time usage for different hypothetic "moves to go"-values and choose the
   // minimum of calculated search time values. Usually the greatest hypMTG gives the minimum values.
-  for (hypMTG = 1; hypMTG <= (limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon); hypMTG++)
+  for (hypMTG = 1; hypMTG <= (limits.movestogo ? std::min(limits.movestogo, MoveHorizon) : MoveHorizon); ++hypMTG)
   {
       // Calculate thinking time for hypothetic "moves to go"-value
       hypMyTime =  limits.time[us]
@@ -145,17 +144,17 @@ namespace {
   template<TimeType T>
   int remaining(int myTime, int movesToGo, int currentPly, int slowMover)
   {
-    const float TMaxRatio   = (T == OptimumTime ? 1 : MaxRatio);
-    const float TStealRatio = (T == OptimumTime ? 0 : StealRatio);
+    const double TMaxRatio   = (T == OptimumTime ? 1 : MaxRatio);
+    const double TStealRatio = (T == OptimumTime ? 0 : StealRatio);
 
-    int thisMoveImportance = move_importance(currentPly) * slowMover / 100;
+    double thisMoveImportance = double(move_importance(currentPly) * slowMover) / 100;
     int otherMovesImportance = 0;
 
-    for (int i = 1; i < movesToGo; i++)
+    for (int i = 1; i < movesToGo; ++i)
         otherMovesImportance += move_importance(currentPly + 2 * i);
 
-    float ratio1 = (TMaxRatio * thisMoveImportance) / float(TMaxRatio * thisMoveImportance + otherMovesImportance);
-    float ratio2 = (thisMoveImportance + TStealRatio * otherMovesImportance) / float(thisMoveImportance + otherMovesImportance);
+    double ratio1 = (TMaxRatio * thisMoveImportance) / (TMaxRatio * thisMoveImportance + otherMovesImportance);
+    double ratio2 = (thisMoveImportance + TStealRatio * otherMovesImportance) / (thisMoveImportance + otherMovesImportance);
 
     return int(floor(myTime * std::min(ratio1, ratio2)));
   }

src/timeman.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(TIMEMAN_H_INCLUDED)
+#ifndef TIMEMAN_H_INCLUDED
 #define TIMEMAN_H_INCLUDED
 
 /// The TimeManager class computes the optimal time to think depending on the
@@ -26,7 +26,7 @@
 class TimeManager {
 public:
   void init(const Search::LimitsType& limits, int currentPly, Color us);
-  void pv_instability(int curChanges, int prevChanges);
+  void pv_instability(double bestMoveChanges);
   int available_time() const { return optimumSearchTime + unstablePVExtraTime; }
   int maximum_time() const { return maximumSearchTime; }
 
@@ -36,4 +36,4 @@ private:
   int unstablePVExtraTime;
 };
 
-#endif // !defined(TIMEMAN_H_INCLUDED)
+#endif // #ifndef TIMEMAN_H_INCLUDED

src/tt.cpp

@@ -40,17 +40,17 @@ void TranspositionTable::set_size(size_t mbSize) {
       return;
 
   hashMask = size - ClusterSize;
-  delete [] table;
-  table = new (std::nothrow) TTEntry[size];
+  free(mem);
+  mem = calloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1, 1);
 
-  if (!table)
+  if (!mem)
   {
       std::cerr << "Failed to allocate " << mbSize
                 << "MB for transposition table." << std::endl;
       exit(EXIT_FAILURE);
   }
 
-  clear(); // Operator new is not guaranteed to initialize memory to zero
+  table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
 }
 
 
@@ -60,7 +60,24 @@ void TranspositionTable::set_size(size_t mbSize) {
 
 void TranspositionTable::clear() {
 
-  memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
+  std::memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
+}
+
+
+/// TranspositionTable::probe() looks up the current position in the
+/// transposition table. Returns a pointer to the TTEntry or NULL if
+/// position is not found.
+
+const TTEntry* TranspositionTable::probe(const Key key) const {
+
+  const TTEntry* tte = first_entry(key);
+  uint32_t key32 = key >> 32;
+
+  for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
+      if (tte->key() == key32)
+          return tte;
+
+  return NULL;
 }
 
 
@@ -72,7 +89,7 @@ void TranspositionTable::clear() {
 /// more valuable than a TTEntry t2 if t1 is from the current search and t2 is from
 /// a previous search, or if the depth of t1 is bigger than the depth of t2.
 
-void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m, Value statV, Value kingD) {
+void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
 
   int c1, c2, c3;
   TTEntry *tte, *replace;
@@ -80,42 +97,25 @@ void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m,
 
   tte = replace = first_entry(key);
 
-  for (unsigned i = 0; i < ClusterSize; i++, tte++)
+  for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
   {
       if (!tte->key() || tte->key() == key32) // Empty or overwrite old
       {
-          // Preserve any existing ttMove
-          if (m == MOVE_NONE)
-              m = tte->move();
+          if (!m)
+              m = tte->move(); // Preserve any existing ttMove
 
-          tte->save(key32, v, t, d, m, generation, statV, kingD);
-          return;
+          replace = tte;
+          break;
       }
 
       // Implement replace strategy
       c1 = (replace->generation() == generation ?  2 : 0);
-      c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
+      c2 = (tte->generation() == generation || tte->bound() == BOUND_EXACT ? -2 : 0);
       c3 = (tte->depth() < replace->depth() ?  1 : 0);
 
       if (c1 + c2 + c3 > 0)
           replace = tte;
   }
-  replace->save(key32, v, t, d, m, generation, statV, kingD);
-}
-
-
-/// TranspositionTable::probe() looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL if
-/// position is not found.
-
-TTEntry* TranspositionTable::probe(const Key key) const {
-
-  TTEntry* tte = first_entry(key);
-  uint32_t key32 = key >> 32;
-
-  for (unsigned i = 0; i < ClusterSize; i++, tte++)
-      if (tte->key() == key32)
-          return tte;
-
-  return NULL;
+
+  replace->save(key32, v, b, d, m, generation, statV);
 }

src/tt.h

@@ -17,60 +17,50 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(TT_H_INCLUDED)
+#ifndef TT_H_INCLUDED
 #define TT_H_INCLUDED
 
 #include "misc.h"
 #include "types.h"
 
-/// The TTEntry is the class of transposition table entries
+/// The TTEntry is the 128 bit transposition table entry, defined as below:
 ///
-/// A TTEntry needs 128 bits to be stored
-///
-/// bit  0-31: key
-/// bit 32-63: data
-/// bit 64-79: value
-/// bit 80-95: depth
-/// bit 96-111: static value
-/// bit 112-127: margin of static value
-///
-/// the 32 bits of the data field are so defined
-///
-/// bit  0-15: move
-/// bit 16-20: not used
-/// bit 21-22: value type
-/// bit 23-31: generation
+/// key: 32 bit
+/// move: 16 bit
+/// bound type: 8 bit
+/// generation: 8 bit
+/// value: 16 bit
+/// depth: 16 bit
+/// static value: 16 bit
+/// static margin: 16 bit
 
-class TTEntry {
+struct TTEntry {
 
-public:
-  void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g, Value ev, Value em) {
+  void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g, Value ev) {
 
     key32        = (uint32_t)k;
     move16       = (uint16_t)m;
-    bound        = (uint8_t)b;
+    bound8       = (uint8_t)b;
     generation8  = (uint8_t)g;
     value16      = (int16_t)v;
     depth16      = (int16_t)d;
     evalValue    = (int16_t)ev;
-    evalMargin   = (int16_t)em;
   }
-  void set_generation(int g) { generation8 = (uint8_t)g; }
+  void set_generation(uint8_t g) { generation8 = g; }
 
   uint32_t key() const      { return key32; }
   Depth depth() const       { return (Depth)depth16; }
   Move move() const         { return (Move)move16; }
   Value value() const       { return (Value)value16; }
-  Bound type() const        { return (Bound)bound; }
+  Bound bound() const       { return (Bound)bound8; }
   int generation() const    { return (int)generation8; }
   Value eval_value() const  { return (Value)evalValue; }
-  Value eval_margin() const { return (Value)evalMargin; }
 
 private:
   uint32_t key32;
   uint16_t move16;
-  uint8_t bound, generation8;
-  int16_t value16, depth16, evalValue, evalMargin;
+  uint8_t bound8, generation8;
+  int16_t value16, depth16, evalValue;
 };
 
 
@@ -85,20 +75,21 @@ class TranspositionTable {
   static const unsigned ClusterSize = 4; // A cluster is 64 Bytes
 
 public:
- ~TranspositionTable() { delete [] table; }
-  void new_search() { generation++; }
+ ~TranspositionTable() { free(mem); }
+  void new_search() { ++generation; }
 
-  TTEntry* probe(const Key key) const;
+  const TTEntry* probe(const Key key) const;
   TTEntry* first_entry(const Key key) const;
   void refresh(const TTEntry* tte) const;
   void set_size(size_t mbSize);
   void clear();
-  void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV, Value kingD);
+  void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
 
 private:
   uint32_t hashMask;
   TTEntry* table;
-  uint8_t generation; // Size must be not bigger then TTEntry::generation8
+  void* mem;
+  uint8_t generation; // Size must be not bigger than TTEntry::generation8
 };
 
 extern TranspositionTable TT;
@@ -122,4 +113,4 @@ inline void TranspositionTable::refresh(const TTEntry* tte) const {
   const_cast<TTEntry*>(tte)->set_generation(generation);
 }
 
-#endif // !defined(TT_H_INCLUDED)
+#endif // #ifndef TT_H_INCLUDED

src/types.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(TYPES_H_INCLUDED)
+#ifndef TYPES_H_INCLUDED
 #define TYPES_H_INCLUDED
 
 /// For Linux and OSX configuration is done automatically using Makefile. To get
@@ -42,6 +42,8 @@
 
 #include "platform.h"
 
+#define unlikely(x) (x) // For code annotation purposes
+
 #if defined(_WIN64) && !defined(IS_64BIT)
 #  include <intrin.h> // MSVC popcnt and bsfq instrinsics
 #  define IS_64BIT
@@ -56,13 +58,14 @@
 #   include <xmmintrin.h> // Intel and Microsoft header for _mm_prefetch()
 #  endif
 
+#define CACHE_LINE_SIZE 64
 #if defined(_MSC_VER) || defined(__INTEL_COMPILER)
-#  define CACHE_LINE_ALIGNMENT __declspec(align(64))
+#  define CACHE_LINE_ALIGNMENT __declspec(align(CACHE_LINE_SIZE))
 #else
-#  define CACHE_LINE_ALIGNMENT  __attribute__ ((aligned(64)))
+#  define CACHE_LINE_ALIGNMENT  __attribute__ ((aligned(CACHE_LINE_SIZE)))
 #endif
 
-#if defined(_MSC_VER)
+#ifdef _MSC_VER
 #  define FORCE_INLINE  __forceinline
 #elif defined(__GNUC__)
 #  define FORCE_INLINE  inline __attribute__((always_inline))
@@ -70,13 +73,13 @@
 #  define FORCE_INLINE  inline
 #endif
 
-#if defined(USE_POPCNT)
+#ifdef USE_POPCNT
 const bool HasPopCnt = true;
 #else
 const bool HasPopCnt = false;
 #endif
 
-#if defined(IS_64BIT)
+#ifdef IS_64BIT
 const bool Is64Bit = true;
 #else
 const bool Is64Bit = false;
@@ -85,28 +88,9 @@ const bool Is64Bit = false;
 typedef uint64_t Key;
 typedef uint64_t Bitboard;
 
-const int MAX_MOVES      = 192;
+const int MAX_MOVES      = 256;
 const int MAX_PLY        = 100;
-const int MAX_PLY_PLUS_2 = MAX_PLY + 2;
-
-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;
-
-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);
-
+const int MAX_PLY_PLUS_6 = MAX_PLY + 6;
 
 /// A move needs 16 bits to be stored
 ///
@@ -120,24 +104,24 @@ const Bitboard Rank8BB = Rank1BB << (8 * 7);
 /// while MOVE_NONE and MOVE_NULL have the same origin and destination square.
 
 enum Move {
-  MOVE_NONE = 0,
+  MOVE_NONE,
   MOVE_NULL = 65
 };
 
 enum MoveType {
-  NORMAL    = 0,
+  NORMAL,
   PROMOTION = 1 << 14,
   ENPASSANT = 2 << 14,
   CASTLE    = 3 << 14
 };
 
 enum CastleRight {  // Defined as in PolyGlot book hash key
-  CASTLES_NONE = 0,
-  WHITE_OO     = 1,
-  WHITE_OOO    = 2,
-  BLACK_OO     = 4,
-  BLACK_OOO    = 8,
-  ALL_CASTLES  = 15,
+  CASTLES_NONE,
+  WHITE_OO,
+  WHITE_OOO   = WHITE_OO << 1,
+  BLACK_OO    = WHITE_OO << 2,
+  BLACK_OOO   = WHITE_OO << 3,
+  ALL_CASTLES = WHITE_OO | WHITE_OOO | BLACK_OO | BLACK_OOO,
   CASTLE_RIGHT_NB = 16
 };
 
@@ -148,7 +132,7 @@ enum CastlingSide {
 };
 
 enum Phase {
-  PHASE_ENDGAME = 0,
+  PHASE_ENDGAME,
   PHASE_MIDGAME = 128,
   MG = 0, EG = 1, PHASE_NB = 2
 };
@@ -161,9 +145,9 @@ enum ScaleFactor {
 };
 
 enum Bound {
-  BOUND_NONE  = 0,
-  BOUND_UPPER = 1,
-  BOUND_LOWER = 2,
+  BOUND_NONE,
+  BOUND_UPPER,
+  BOUND_LOWER,
   BOUND_EXACT = BOUND_UPPER | BOUND_LOWER
 };
 
@@ -189,15 +173,15 @@ enum Value {
 };
 
 enum PieceType {
-  NO_PIECE_TYPE = 0, ALL_PIECES = 0,
-  PAWN = 1, KNIGHT = 2, BISHOP = 3, ROOK = 4, QUEEN = 5, KING = 6,
+  NO_PIECE_TYPE, PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING,
+  ALL_PIECES = 0,
   PIECE_TYPE_NB = 8
 };
 
 enum Piece {
-  NO_PIECE = 0,
-  W_PAWN = 1, W_KNIGHT =  2, W_BISHOP =  3, W_ROOK =  4, W_QUEEN =  5, W_KING =  6,
-  B_PAWN = 9, B_KNIGHT = 10, B_BISHOP = 11, B_ROOK = 12, B_QUEEN = 13, B_KING = 14,
+  NO_PIECE,
+  W_PAWN = 1, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
+  B_PAWN = 9, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING,
   PIECE_NB = 16
 };
 
@@ -210,8 +194,8 @@ enum Depth {
   ONE_PLY = 2,
 
   DEPTH_ZERO          =  0 * ONE_PLY,
-  DEPTH_QS_CHECKS     = -1 * ONE_PLY,
-  DEPTH_QS_NO_CHECKS  = -2 * ONE_PLY,
+  DEPTH_QS_CHECKS     =  0 * ONE_PLY,
+  DEPTH_QS_NO_CHECKS  = -1 * ONE_PLY,
   DEPTH_QS_RECAPTURES = -5 * ONE_PLY,
 
   DEPTH_NONE = -127 * ONE_PLY
@@ -244,11 +228,11 @@ enum Square {
 };
 
 enum File {
-  FILE_A, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H, FILE_NB = 8
+  FILE_A, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H, FILE_NB
 };
 
 enum Rank {
-  RANK_1, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8, RANK_NB = 8
+  RANK_1, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8, RANK_NB
 };
 
 
@@ -257,7 +241,7 @@ enum Rank {
 /// for midgame value. Compiler is free to choose the enum type as long as can
 /// keep its data, so ensure Score to be an integer type.
 enum Score {
-  SCORE_ZERO = 0,
+  SCORE_ZERO,
   SCORE_ENSURE_INTEGER_SIZE_P = INT_MAX,
   SCORE_ENSURE_INTEGER_SIZE_N = INT_MIN
 };
@@ -267,7 +251,7 @@ inline Score make_score(int mg, int eg) { return Score((mg << 16) + eg); }
 /// Extracting the signed lower and upper 16 bits it not so trivial because
 /// according to the standard a simple cast to short is implementation defined
 /// and so is a right shift of a signed integer.
-inline Value mg_value(Score s) { return Value(((s + 32768) & ~0xffff) / 0x10000); }
+inline Value mg_value(Score s) { return Value(((s + 0x8000) & ~0xffff) / 0x10000); }
 
 /// On Intel 64 bit we have a small speed regression with the standard conforming
 /// version, so use a faster code in this case that, although not 100% standard
@@ -290,15 +274,15 @@ inline T operator-(const T d1, const T d2) { return T(int(d1) - int(d2)); } \
 inline T operator*(int i, const T d) { return T(i * int(d)); }              \
 inline T operator*(const T d, int i) { return T(int(d) * i); }              \
 inline T operator-(const T d) { return T(-int(d)); }                        \
-inline T& operator+=(T& d1, const T d2) { d1 = d1 + d2; return d1; }        \
-inline T& operator-=(T& d1, const T d2) { d1 = d1 - d2; return d1; }        \
-inline T& operator*=(T& d, int i) { d = T(int(d) * i); return d; }
+inline T& operator+=(T& d1, const T d2) { return d1 = d1 + d2; }            \
+inline T& operator-=(T& d1, const T d2) { return d1 = d1 - d2; }            \
+inline T& operator*=(T& d, int i) { return d = T(int(d) * i); }
 
 #define ENABLE_OPERATORS_ON(T) ENABLE_SAFE_OPERATORS_ON(T)                  \
-inline T operator++(T& d, int) { d = T(int(d) + 1); return d; }             \
-inline T operator--(T& d, int) { d = T(int(d) - 1); return d; }             \
+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/(const T d, int i) { return T(int(d) / i); }              \
-inline T& operator/=(T& d, int i) { d = T(int(d) / i); return d; }
+inline T& operator/=(T& d, int i) { return d = T(int(d) / i); }
 
 ENABLE_OPERATORS_ON(Value)
 ENABLE_OPERATORS_ON(PieceType)
@@ -324,47 +308,26 @@ inline Score operator/(Score s, int i) {
   return make_score(mg_value(s) / i, eg_value(s) / i);
 }
 
-/// Weight score v by score w trying to prevent overflow
-inline Score apply_weight(Score v, Score w) {
-  return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
-                    (int(eg_value(v)) * eg_value(w)) / 0x100);
-}
-
 #undef ENABLE_OPERATORS_ON
 #undef ENABLE_SAFE_OPERATORS_ON
 
-namespace Zobrist {
-
-  extern Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB];
-  extern Key enpassant[FILE_NB];
-  extern Key castle[CASTLE_RIGHT_NB];
-  extern Key side;
-  extern Key exclusion;
-
-  void init();
-}
-
-CACHE_LINE_ALIGNMENT
-
-extern Score pieceSquareTable[PIECE_NB][SQUARE_NB];
 extern Value PieceValue[PHASE_NB][PIECE_NB];
-extern int SquareDistance[SQUARE_NB][SQUARE_NB];
 
-struct MoveStack {
+struct ExtMove {
   Move move;
   int score;
 };
 
-inline bool operator<(const MoveStack& f, const MoveStack& s) {
+inline bool operator<(const ExtMove& f, const ExtMove& s) {
   return f.score < s.score;
 }
 
 inline Color operator~(Color c) {
-  return Color(c ^ 1);
+  return Color(c ^ BLACK);
 }
 
 inline Square operator~(Square s) {
-  return Square(s ^ 56); // Vertical flip SQ_A1 -> SQ_A8
+  return Square(s ^ SQ_A8); // Vertical flip SQ_A1 -> SQ_A8
 }
 
 inline Square operator|(File f, Rank r) {
@@ -408,10 +371,6 @@ inline Rank rank_of(Square s) {
   return Rank(s >> 3);
 }
 
-inline Square mirror(Square s) {
-  return Square(s ^ 7); // Horizontal flip SQ_A1 -> SQ_H1
-}
-
 inline Square relative_square(Color c, Square s) {
   return Square(s ^ (c * 56));
 }
@@ -429,18 +388,6 @@ inline bool opposite_colors(Square s1, Square s2) {
   return ((s >> 3) ^ s) & 1;
 }
 
-inline int file_distance(Square s1, Square s2) {
-  return abs(file_of(s1) - file_of(s2));
-}
-
-inline int rank_distance(Square s1, Square s2) {
-  return abs(rank_of(s1) - rank_of(s2));
-}
-
-inline int square_distance(Square s1, Square s2) {
-  return SquareDistance[s1][s2];
-}
-
 inline char file_to_char(File f, bool tolower = true) {
   return char(f - FILE_A + (tolower ? 'a' : 'A'));
 }
@@ -489,4 +436,4 @@ inline const std::string square_to_string(Square s) {
   return ch;
 }
 
-#endif // !defined(TYPES_H_INCLUDED)
+#endif // #ifndef TYPES_H_INCLUDED

src/uci.cpp

@@ -42,8 +42,8 @@ namespace {
   // position just before to start searching). Needed by repetition draw detection.
   Search::StateStackPtr SetupStates;
 
-  void set_option(istringstream& up);
-  void set_position(Position& pos, istringstream& up);
+  void setoption(istringstream& up);
+  void position(Position& pos, istringstream& up);
   void go(const Position& pos, istringstream& up);
 }
 
@@ -55,7 +55,7 @@ namespace {
 
 void UCI::loop(const string& args) {
 
-  Position pos(StartFEN, false, Threads.main_thread()); // The root position
+  Position pos(StartFEN, false, Threads.main()); // The root position
   string token, cmd = args;
 
   do {
@@ -76,7 +76,7 @@ void UCI::loop(const string& args) {
           if (token != "ponderhit" || Search::Signals.stopOnPonderhit)
           {
               Search::Signals.stop = true;
-              Threads.main_thread()->notify_one(); // Could be sleeping
+              Threads.main()->notify_one(); // Could be sleeping
           }
           else
               Search::Limits.ponder = false;
@@ -102,15 +102,19 @@ void UCI::loop(const string& args) {
                     << "\n"       << Options
                     << "\nuciok"  << sync_endl;
 
+      else if (token == "eval")
+      {
+          Search::RootColor = pos.side_to_move(); // Ensure it is set
+          sync_cout << Eval::trace(pos) << sync_endl;
+      }
       else if (token == "ucinewgame") { /* Avoid returning "Unknown command" */ }
       else if (token == "go")         go(pos, is);
-      else if (token == "position")   set_position(pos, is);
-      else if (token == "setoption")  set_option(is);
+      else if (token == "position")   position(pos, is);
+      else if (token == "setoption")  setoption(is);
       else if (token == "flip")       pos.flip();
       else if (token == "bench")      benchmark(pos, is);
       else if (token == "d")          sync_cout << pos.pretty() << sync_endl;
       else if (token == "isready")    sync_cout << "readyok" << sync_endl;
-      else if (token == "eval")       sync_cout << Eval::trace(pos) << sync_endl;
       else
           sync_cout << "Unknown command: " << cmd << sync_endl;
 
@@ -122,12 +126,12 @@ void UCI::loop(const string& args) {
 
 namespace {
 
-  // set_position() is called when engine receives the "position" UCI command.
+  // 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 set_position(Position& pos, istringstream& is) {
+  void position(Position& pos, istringstream& is) {
 
     Move m;
     string token, fen;
@@ -145,7 +149,7 @@ namespace {
     else
         return;
 
-    pos.set(fen, Options["UCI_Chess960"], Threads.main_thread());
+    pos.set(fen, Options["UCI_Chess960"], Threads.main());
     SetupStates = Search::StateStackPtr(new std::stack<StateInfo>());
 
     // Parse move list (if any)
@@ -157,10 +161,10 @@ namespace {
   }
 
 
-  // set_option() is called when engine receives the "setoption" UCI command. The
+  // setoption() is called when engine receives the "setoption" UCI command. The
   // function updates the UCI option ("name") to the given value ("value").
 
-  void set_option(istringstream& is) {
+  void setoption(istringstream& is) {
 
     string token, name, value;
 

src/ucioption.cpp

@@ -51,31 +51,28 @@ bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const
 
 
 /// init() initializes the UCI options to their hard coded default values
-/// and initializes the default value of "Threads" and "Min Split Depth"
-/// parameters according to the number of CPU cores detected.
 
 void init(OptionsMap& o) {
 
-  int cpus = std::min(cpu_count(), MAX_THREADS);
-  int msd = cpus < 8 ? 4 : 7;
-
-  o["Use Debug Log"]               = Option(false, on_logger);
-  o["Use Search Log"]              = Option(false);
+  o["Write Debug Log"]             = Option(false, on_logger);
+  o["Write Search Log"]            = Option(false);
   o["Search Log Filename"]         = Option("SearchLog.txt");
   o["Book File"]                   = Option("book.bin");
   o["Best Book Move"]              = Option(false);
   o["Contempt Factor"]             = Option(0, -50,  50);
-  o["Mobility (Middle Game)"]      = Option(100, 0, 200, on_eval);
+  o["Mobility (Midgame)"]          = Option(100, 0, 200, on_eval);
   o["Mobility (Endgame)"]          = Option(100, 0, 200, on_eval);
-  o["Passed Pawns (Middle Game)"]  = Option(100, 0, 200, on_eval);
+  o["Pawn Structure (Midgame)"]    = Option(100, 0, 200, on_eval);
+  o["Pawn Structure (Endgame)"]    = Option(100, 0, 200, on_eval);
+  o["Passed Pawns (Midgame)"]      = Option(100, 0, 200, on_eval);
   o["Passed Pawns (Endgame)"]      = Option(100, 0, 200, on_eval);
   o["Space"]                       = Option(100, 0, 200, on_eval);
   o["Aggressiveness"]              = Option(100, 0, 200, on_eval);
   o["Cowardice"]                   = Option(100, 0, 200, on_eval);
-  o["Min Split Depth"]             = Option(msd, 4, 12, on_threads);
-  o["Max Threads per Split Point"] = Option(5, 4, 8, on_threads);
-  o["Threads"]                     = Option(cpus, 1, MAX_THREADS, on_threads);
-  o["Use Sleeping Threads"]        = Option(false);
+  o["Min Split Depth"]             = Option(0, 0, 12, on_threads);
+  o["Max Threads per Split Point"] = Option(5, 4,  8, on_threads);
+  o["Threads"]                     = Option(1, 1, MAX_THREADS, on_threads);
+  o["Idle Threads Sleep"]          = Option(false);
   o["Hash"]                        = Option(32, 1, 8192, on_hash_size);
   o["Clear Hash"]                  = Option(on_clear_hash);
   o["Ponder"]                      = Option(true);
@@ -83,10 +80,10 @@ void init(OptionsMap& o) {
   o["MultiPV"]                     = Option(1, 1, 500);
   o["Skill Level"]                 = Option(20, 0, 20);
   o["Emergency Move Horizon"]      = Option(40, 0, 50);
-  o["Emergency Base Time"]         = Option(200, 0, 30000);
-  o["Emergency Move Time"]         = Option(70, 0, 5000);
+  o["Emergency Base Time"]         = Option(60, 0, 30000);
+  o["Emergency Move Time"]         = Option(30, 0, 5000);
   o["Minimum Thinking Time"]       = Option(20, 0, 5000);
-  o["Slow Mover"]                  = Option(100, 10, 1000);
+  o["Slow Mover"]                  = Option(70, 10, 1000);
   o["UCI_Chess960"]                = Option(false);
   o["UCI_AnalyseMode"]             = Option(false, on_eval);
 }
@@ -97,7 +94,7 @@ void init(OptionsMap& o) {
 
 std::ostream& operator<<(std::ostream& os, const OptionsMap& om) {
 
-  for (size_t idx = 0; idx < om.size(); idx++)
+  for (size_t idx = 0; idx < om.size(); ++idx)
       for (OptionsMap::const_iterator it = om.begin(); it != om.end(); ++it)
           if (it->second.idx == idx)
           {

src/ucioption.h

@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(UCIOPTION_H_INCLUDED)
+#ifndef UCIOPTION_H_INCLUDED
 #define UCIOPTION_H_INCLUDED
 
 #include <map>
@@ -66,4 +66,4 @@ void loop(const std::string&);
 
 extern UCI::OptionsMap Options;
 
-#endif // !defined(UCIOPTION_H_INCLUDED)
+#endif // #ifndef UCIOPTION_H_INCLUDED