X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=54df6c2d61878546202eeb07bded007df8b19489;hp=f6f1eba681e6d0030d0e8dccba75565bf9c82070;hb=12e79be91039796299187ba1b2f1559552642ea4;hpb=6c040c821a50475840607ef5f11c270ee21d61da diff --git a/src/bitboard.h b/src/bitboard.h index f6f1eba6..54df6c2d 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -2,13 +2,13 @@ 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) 2015-2018 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 the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the @@ -39,81 +39,102 @@ 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; -extern int SquareDistance[SQUARE_NB][SQUARE_NB]; +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; -extern Bitboard RookMasks [SQUARE_NB]; -extern Bitboard RookMagics [SQUARE_NB]; -extern Bitboard* RookAttacks[SQUARE_NB]; -extern unsigned RookShifts [SQUARE_NB]; +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 Bitboard BishopMasks [SQUARE_NB]; -extern Bitboard BishopMagics [SQUARE_NB]; -extern Bitboard* BishopAttacks[SQUARE_NB]; -extern unsigned BishopShifts [SQUARE_NB]; +extern int SquareDistance[SQUARE_NB][SQUARE_NB]; extern Bitboard SquareBB[SQUARE_NB]; extern Bitboard FileBB[FILE_NB]; extern Bitboard RankBB[RANK_NB]; extern Bitboard AdjacentFilesBB[FILE_NB]; -extern Bitboard InFrontBB[COLOR_NB][RANK_NB]; -extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB]; +extern Bitboard ForwardRanksBB[COLOR_NB][RANK_NB]; extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; extern Bitboard DistanceRingBB[SQUARE_NB][8]; -extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB]; +extern Bitboard ForwardFileBB[COLOR_NB][SQUARE_NB]; extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; + + +/// Magic holds all magic bitboards relevant data for a single square +struct Magic { + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; + + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { + + if (HasPext) + return unsigned(pext(occupied, mask)); + + if (Is64Bit) + return unsigned(((occupied & mask) * magic) >> shift); + + unsigned lo = unsigned(occupied) & unsigned(mask); + unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32); + return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift; + } +}; + +extern Magic RookMagics[SQUARE_NB]; +extern Magic BishopMagics[SQUARE_NB]; /// Overloads of bitwise operators between a Bitboard and a Square for testing /// whether a given bit is set in a bitboard, and for setting and clearing bits. inline Bitboard operator&(Bitboard b, Square s) { + assert(s >= SQ_A1 && s <= SQ_H8); return b & SquareBB[s]; } inline Bitboard operator|(Bitboard b, Square s) { + assert(s >= SQ_A1 && s <= SQ_H8); return b | SquareBB[s]; } inline Bitboard operator^(Bitboard b, Square s) { + assert(s >= SQ_A1 && s <= SQ_H8); return b ^ SquareBB[s]; } inline Bitboard& operator|=(Bitboard& b, Square s) { + assert(s >= SQ_A1 && s <= SQ_H8); return b |= SquareBB[s]; } inline Bitboard& operator^=(Bitboard& b, Square s) { + assert(s >= SQ_A1 && s <= SQ_H8); return b ^= SquareBB[s]; } -inline bool more_than_one(Bitboard b) { +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } - /// rank_bb() and file_bb() return a bitboard representing all the squares on /// the given file or rank. @@ -134,17 +155,28 @@ inline Bitboard file_bb(Square s) { } -/// shift_bb() moves a bitboard one step along direction Delta. Mainly for pawns +/// shift() moves a bitboard one step along direction D (mainly for pawns) -template -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 +template +constexpr Bitboard shift(Bitboard b) { + return D == NORTH ? b << 8 : D == SOUTH ? b >> 8 + : 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. @@ -163,28 +195,28 @@ inline Bitboard between_bb(Square s1, Square s2) { } -/// in_front_bb() returns a bitboard representing all the squares on all the ranks -/// in front of the given one, from the point of view of the given color. For -/// instance, in_front_bb(BLACK, RANK_3) will return the squares on ranks 1 and 2. +/// forward_ranks_bb() returns a bitboard representing the squares on all the ranks +/// in front of the given one, from the point of view of the given color. For instance, +/// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2. -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; +inline Bitboard forward_ranks_bb(Color c, Square s) { + return ForwardRanksBB[c][rank_of(s)]; } -/// forward_bb() returns a bitboard representing all the squares along the line +/// forward_file_bb() returns a bitboard representing all the squares along the line /// in front of the given one, from the point of view of the given color: -/// ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s) +/// ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s) -inline Bitboard forward_bb(Color c, Square s) { - return ForwardBB[c][s]; +inline Bitboard forward_file_bb(Color c, Square s) { + return ForwardFileBB[c][s]; } /// pawn_attack_span() returns a bitboard representing all the squares that can be /// attacked by a pawn of the given color when it moves along its file, starting /// from the given square: -/// PawnAttackSpan[c][s] = in_front_bb(c, s) & adjacent_files_bb(s); +/// PawnAttackSpan[c][s] = forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s)); inline Bitboard pawn_attack_span(Color c, Square s) { return PawnAttackSpan[c][s]; @@ -193,21 +225,13 @@ 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]; } -/// squares_of_color() returns a bitboard representing all the squares of the -/// same color of the given one. - -inline Bitboard squares_of_color(Square s) { - return DarkSquares & s ? DarkSquares : ~DarkSquares; -} - - /// aligned() returns true if the squares s1, s2 and s3 are aligned either on a /// straight or on a diagonal line. @@ -228,96 +252,116 @@ 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. -template -inline unsigned magic_index(Square s, Bitboard occupied) { - - Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks; - Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics; - unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts; - - if (HasPext) - return unsigned(pext(occupied, Masks[s])); - - if (Is64Bit) - return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]); - - unsigned lo = unsigned(occupied) & unsigned(Masks[s]); - unsigned hi = unsigned(occupied >> 32) & unsigned(Masks[s] >> 32); - return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s]; -} +/// piece of type Pt (bishop or rook) placed on 's'. template inline Bitboard attacks_bb(Square s, Bitboard occupied) { - return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index(s, occupied)]; + + const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; + return m.attacks[m.index(occupied)]; } -inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) { +inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { + + assert(pt != PAWN); - switch (type_of(pc)) + switch (pt) { case BISHOP: return attacks_bb(s, occupied); - case ROOK : return attacks_bb(s, occupied); + case ROOK : return attacks_bb< ROOK>(s, occupied); case QUEEN : return attacks_bb(s, occupied) | attacks_bb(s, occupied); - default : return StepAttacksBB[pc][s]; + default : return PseudoAttacks[pt][s]; } } +/// popcount() counts the number of non-zero bits in a bitboard + +inline int popcount(Bitboard b) { + +#ifndef USE_POPCNT + + extern uint8_t PopCnt16[1 << 16]; + union { Bitboard bb; uint16_t u[4]; } v = { b }; + return PopCnt16[v.u[0]] + PopCnt16[v.u[1]] + PopCnt16[v.u[2]] + PopCnt16[v.u[3]]; + +#elif defined(_MSC_VER) || defined(__INTEL_COMPILER) + + return (int)_mm_popcnt_u64(b); + +#else // Assumed gcc or compatible compiler + + return __builtin_popcountll(b); + +#endif +} + + /// lsb() and msb() return the least/most significant bit in a non-zero bitboard -#ifdef USE_BSFQ +#if defined(__GNUC__) // GCC, Clang, ICC + +inline Square lsb(Bitboard b) { + assert(b); + return Square(__builtin_ctzll(b)); +} + +inline Square msb(Bitboard b) { + assert(b); + return Square(63 ^ __builtin_clzll(b)); +} + +#elif defined(_MSC_VER) // MSVC -# if defined(_MSC_VER) && !defined(__INTEL_COMPILER) +#ifdef _WIN64 // MSVC, WIN64 inline Square lsb(Bitboard b) { + assert(b); unsigned long idx; _BitScanForward64(&idx, b); return (Square) idx; } inline Square msb(Bitboard b) { + assert(b); unsigned long idx; _BitScanReverse64(&idx, b); return (Square) idx; } -# elif defined(__arm__) - -inline int lsb32(uint32_t v) { - __asm__("rbit %0, %1" : "=r"(v) : "r"(v)); - return __builtin_clz(v); -} - -inline Square msb(Bitboard b) { - return (Square) (63 - __builtin_clzll(b)); -} +#else // MSVC, WIN32 inline Square lsb(Bitboard b) { - return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32))); -} - -# else // Assumed gcc or compatible compiler + assert(b); + unsigned long idx; -inline Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen - Bitboard idx; - __asm__("bsfq %1, %0": "=r"(idx): "rm"(b) ); - return (Square) 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) { - Bitboard idx; - __asm__("bsrq %1, %0": "=r"(idx): "rm"(b) ); - return (Square) idx; + 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 +#endif -#else // ifdef(USE_BSFQ) +#else // Compiler is neither GCC nor MSVC compatible -Square lsb(Bitboard b); -Square msb(Bitboard b); +#error "Compiler not supported." #endif