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Change definition of between_bb()

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We remark that in current master, most of our use cases for between_bb() can be
optimized if the second parameter of the function is added to the segment. So we
change the definition of between_bb(s1, s2) such that it excludes s1 but includes s2.

We also use a precomputed array for between_bb() for another small speed gain
(see https://tests.stockfishchess.org/tests/view/604d09f72433018de7a389fb).

Passed STC:
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 18736 W: 1746 L: 1607 D: 15383
Ptnml(0-2): 61, 1226, 6644, 1387, 50
https://tests.stockfishchess.org/tests/view/60428c84ddcba5f0627bb6e4

Yellow LTC:
LTC:
LLR: -3.00 (-2.94,2.94) {0.25,1.25}
Total: 39144 W: 1431 L: 1413 D: 36300
Ptnml(0-2): 13, 1176, 17184, 1178, 21
https://tests.stockfishchess.org/tests/view/605128702433018de7a38ca1

Closes https://github.com/official-stockfish/Stockfish/pull/3397

---------

Verified for correctness by running perft on the following position:

./stockfish
position fen 4rrk1/1p1nq3/p7/2p1P1pp/3P2bp/3Q1Bn1/PPPB4/1K2R1NR w - - 40 21
go perft 6

Nodes searched: 6136386434

--------

No functional change
This commit is contained in:
bmc4
2021-03-15 16:06:42 -03:00
committed by Stéphane Nicolet
parent d58e83695f
commit 5089061659
4 changed files with 27 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/position.cpp
+4 -4
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@@ -320,7 +320,7 @@ void Position::set_castling_right(Color c, Square rfrom) {
Square kto = relative_square(c, cr & KING_SIDE ? SQ_G1 : SQ_C1);
Square rto = relative_square(c, cr & KING_SIDE ? SQ_F1 : SQ_D1);
castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto) | rto | kto)
castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto))
& ~(kfrom | rfrom);
}
@@ -613,8 +613,8 @@ bool Position::pseudo_legal(const Move m) const {
if (more_than_one(checkers()))
return false;
// Our move must be a blocking evasion or a capture of the checking piece
if (!((between_bb(lsb(checkers()), square<KING>(us)) | checkers()) & to))
// Our move must be a blocking interposition or a capture of the checking piece
if (!(between_bb(square<KING>(us), lsb(checkers())) & to))
return false;
}
// In case of king moves under check we have to remove king so as to catch
@@ -1218,7 +1218,7 @@ bool Position::has_game_cycle(int ply) const {
Square s1 = from_sq(move);
Square s2 = to_sq(move);
if (!(between_bb(s1, s2) & pieces()))
if (!((between_bb(s1, s2) ^ s2) & pieces()))
{
if (ply > i)
return true;