X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=3d629de1abe986d63cbf3801f7d1a421cb8006ed;hp=63f668b9b8a7307243c1146d55e079c1a713e5d7;hb=f0f6da2d30fc005fd0fa126ee1eefd11fe10a604;hpb=2c237da54647bb7526f3512bea183eb44919cdda diff --git a/src/bitboard.h b/src/bitboard.h index 63f668b9..3d629de1 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -2,7 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -39,25 +39,26 @@ const std::string pretty(Bitboard b); } -const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; - -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); +constexpr Bitboard AllSquares = ~Bitboard(0); +constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; + +constexpr Bitboard FileABB = 0x0101010101010101ULL; +constexpr Bitboard FileBBB = FileABB << 1; +constexpr Bitboard FileCBB = FileABB << 2; +constexpr Bitboard FileDBB = FileABB << 3; +constexpr Bitboard FileEBB = FileABB << 4; +constexpr Bitboard FileFBB = FileABB << 5; +constexpr Bitboard FileGBB = FileABB << 6; +constexpr Bitboard FileHBB = FileABB << 7; + +constexpr Bitboard Rank1BB = 0xFF; +constexpr Bitboard Rank2BB = Rank1BB << (8 * 1); +constexpr Bitboard Rank3BB = Rank1BB << (8 * 2); +constexpr Bitboard Rank4BB = Rank1BB << (8 * 3); +constexpr Bitboard Rank5BB = Rank1BB << (8 * 4); +constexpr Bitboard Rank6BB = Rank1BB << (8 * 5); +constexpr Bitboard Rank7BB = Rank1BB << (8 * 6); +constexpr Bitboard Rank8BB = Rank1BB << (8 * 7); extern int SquareDistance[SQUARE_NB][SQUARE_NB]; @@ -65,11 +66,11 @@ extern Bitboard SquareBB[SQUARE_NB]; extern Bitboard FileBB[FILE_NB]; extern Bitboard RankBB[RANK_NB]; extern Bitboard AdjacentFilesBB[FILE_NB]; -extern Bitboard InFrontBB[COLOR_NB][RANK_NB]; +extern Bitboard ForwardRanksBB[COLOR_NB][RANK_NB]; extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; extern Bitboard DistanceRingBB[SQUARE_NB][8]; -extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB]; +extern Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB]; extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; @@ -82,6 +83,20 @@ struct Magic { Bitboard magic; Bitboard* attacks; unsigned shift; + + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { + + if (HasPext) + return unsigned(pext(occupied, mask)); + + if (Is64Bit) + return unsigned(((occupied & mask) * magic) >> shift); + + unsigned lo = unsigned(occupied) & unsigned(mask); + unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32); + return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift; + } }; extern Magic RookMagics[SQUARE_NB]; @@ -111,11 +126,10 @@ inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= SquareBB[s]; } -inline bool more_than_one(Bitboard b) { +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } - /// rank_bb() and file_bb() return a bitboard representing all the squares on /// the given file or rank. @@ -136,17 +150,38 @@ inline Bitboard file_bb(Square s) { } -/// shift() moves a bitboard one step along direction D. Mainly for pawns +/// make_bitboard() returns a bitboard from a list of squares -template -inline Bitboard shift(Bitboard b) { +constexpr Bitboard make_bitboard() { return 0; } + +template +constexpr Bitboard make_bitboard(Square s, Squares... squares) { + return (1ULL << s) | make_bitboard(squares...); +} + + +/// shift() moves a bitboard one step along direction D (mainly for pawns) + +template +constexpr Bitboard shift(Bitboard b) { return D == NORTH ? b << 8 : D == SOUTH ? b >> 8 - : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 - : D == NORTH_WEST ? (b & ~FileABB) << 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9 + : D == EAST ? (b & ~FileHBB) << 1 : D == WEST ? (b & ~FileABB) >> 1 + : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == NORTH_WEST ? (b & ~FileABB) << 7 + : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9 : 0; } +/// pawn_attacks_bb() returns the pawn attacks for the given color from the +/// squares in the given bitboard. + +template +constexpr Bitboard pawn_attacks_bb(Bitboard b) { + return C == WHITE ? shift(b) | shift(b) + : shift(b) | shift(b); +} + + /// adjacent_files_bb() returns a bitboard representing all the squares on the /// adjacent files of the given one. @@ -165,28 +200,28 @@ inline Bitboard between_bb(Square s1, Square s2) { } -/// in_front_bb() returns a bitboard representing all the squares on all the ranks -/// in front of the given one, from the point of view of the given color. For -/// instance, in_front_bb(BLACK, RANK_3) will return the squares on ranks 1 and 2. +/// forward_ranks_bb() returns a bitboard representing the squares on all the ranks +/// in front of the given one, from the point of view of the given color. For instance, +/// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2. -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; +inline Bitboard forward_ranks_bb(Color c, Square s) { + return ForwardRanksBB[c][rank_of(s)]; } -/// forward_bb() returns a bitboard representing all the squares along the line +/// forward_file_bb() returns a bitboard representing all the squares along the line /// in front of the given one, from the point of view of the given color: -/// ForwardBB[c][s] = in_front_bb(c, rank_of(s)) & file_bb(s) +/// ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s) -inline Bitboard forward_bb(Color c, Square s) { - return ForwardBB[c][s]; +inline Bitboard forward_file_bb(Color c, Square s) { + return ForwardFileBB[c][s]; } /// pawn_attack_span() returns a bitboard representing all the squares that can be /// attacked by a pawn of the given color when it moves along its file, starting /// from the given square: -/// PawnAttackSpan[c][s] = in_front_bb(c, rank_of(s)) & adjacent_files_bb(file_of(s)); +/// PawnAttackSpan[c][s] = forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s)); inline Bitboard pawn_attack_span(Color c, Square s) { return PawnAttackSpan[c][s]; @@ -195,7 +230,7 @@ inline Bitboard pawn_attack_span(Color c, Square s) { /// passed_pawn_mask() returns a bitboard mask which can be used to test if a /// pawn of the given color and on the given square is a passed pawn: -/// PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_bb(c, s) +/// PassedPawnMask[c][s] = pawn_attack_span(c, s) | forward_file_bb(c, s) inline Bitboard passed_pawn_mask(Color c, Square s) { return PassedPawnMask[c][s]; @@ -222,26 +257,13 @@ template<> inline int distance(Square x, Square y) { return distance(rank_ /// attacks_bb() returns a bitboard representing all the squares attacked by a -/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index() -/// looks up the index using the 'magic bitboards' approach. -inline unsigned magic_index(const Magic& m, Bitboard occupied) { - - if (HasPext) - return unsigned(pext(occupied, m.mask)); - - if (Is64Bit) - return unsigned(((occupied & m.mask) * m.magic) >> m.shift); - - unsigned lo = unsigned(occupied) & unsigned(m.mask); - unsigned hi = unsigned(occupied >> 32) & unsigned(m.mask >> 32); - return (lo * unsigned(m.magic) ^ hi * unsigned(m.magic >> 32)) >> m.shift; -} +/// piece of type Pt (bishop or rook) placed on 's'. template inline Bitboard attacks_bb(Square s, Bitboard occupied) { - const Magic& M = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; - return M.attacks[magic_index(M, occupied)]; + const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; + return m.attacks[m.index(occupied)]; } inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { @@ -282,7 +304,7 @@ inline int popcount(Bitboard b) { /// lsb() and msb() return the least/most significant bit in a non-zero bitboard -#if defined(__GNUC__) +#if defined(__GNUC__) // GCC, Clang, ICC inline Square lsb(Bitboard b) { assert(b); @@ -294,7 +316,9 @@ inline Square msb(Bitboard b) { return Square(63 ^ __builtin_clzll(b)); } -#elif defined(_WIN64) && defined(_MSC_VER) +#elif defined(_MSC_VER) // MSVC + +#ifdef _WIN64 // MSVC, WIN64 inline Square lsb(Bitboard b) { assert(b); @@ -310,12 +334,39 @@ inline Square msb(Bitboard b) { return (Square) idx; } -#else +#else // MSVC, WIN32 + +inline Square lsb(Bitboard b) { + assert(b); + unsigned long idx; + + if (b & 0xffffffff) { + _BitScanForward(&idx, int32_t(b)); + return Square(idx); + } else { + _BitScanForward(&idx, int32_t(b >> 32)); + return Square(idx + 32); + } +} + +inline Square msb(Bitboard b) { + assert(b); + unsigned long idx; + + if (b >> 32) { + _BitScanReverse(&idx, int32_t(b >> 32)); + return Square(idx + 32); + } else { + _BitScanReverse(&idx, int32_t(b)); + return Square(idx); + } +} + +#endif -#define NO_BSF // Fallback on software implementation for other cases +#else // Compiler is neither GCC nor MSVC compatible -Square lsb(Bitboard b); -Square msb(Bitboard b); +#error "Compiler not supported." #endif