X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=b64c92e1a4c54107ef2088ddf43d69c9cafc6871;hp=e3331bd440784c1e2bdec3154012c6f03d2a2c9f;hb=8df1cd10df0869f05916d1eb19e33b66127fcb86;hpb=66a1a7748748db63cb4ff6d7dfb5ba1dabfc9d0b diff --git a/src/bitboard.h b/src/bitboard.h index e3331bd4..b64c92e1 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -1,14 +1,14 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by 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 @@ -18,85 +18,128 @@ along with this program. If not, see . */ -#if !defined(BITBOARD_H_INCLUDED) +#ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include + #include "types.h" -namespace Bitboards { +namespace Bitbases { void init(); -void print(Bitboard b); +bool probe(Square wksq, Square wpsq, Square bksq, Color us); } -namespace Bitbases { +namespace Bitboards { -void init_kpk(); -bool probe_kpk(Square wksq, Square wpsq, Square bksq, Color stm); +void init(); +const std::string pretty(Bitboard b); } -CACHE_LINE_ALIGNMENT +constexpr Bitboard AllSquares = ~Bitboard(0); +constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; -extern Bitboard RMasks[SQUARE_NB]; -extern Bitboard RMagics[SQUARE_NB]; -extern Bitboard* RAttacks[SQUARE_NB]; -extern unsigned RShifts[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 BMasks[SQUARE_NB]; -extern Bitboard BMagics[SQUARE_NB]; -extern Bitboard* BAttacks[SQUARE_NB]; -extern unsigned BShifts[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 int8_t 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 ThisAndAdjacentFilesBB[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 DistanceRingsBB[SQUARE_NB][8]; -extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB]; +extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; +extern Bitboard DistanceRingBB[SQUARE_NB][8]; +extern Bitboard ForwardFileBB[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]; +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) { - return b |= SquareBB[s]; -} - -inline Bitboard& operator^=(Bitboard& b, Square s) { - 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]; +} -/// more_than_one() returns true if in 'b' there is more than one bit set +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); } +inline bool opposite_colors(Square s1, Square s2) { + return bool(DarkSquares & s1) != bool(DarkSquares & s2); +} -/// 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. +/// rank_bb() and file_bb() return a bitboard representing all the squares on +/// the given file or rank. inline Bitboard rank_bb(Rank r) { return RankBB[r]; @@ -115,181 +158,240 @@ inline Bitboard file_bb(Square s) { } -/// adjacent_files_bb takes a file as input and returns a bitboard representing -/// all squares on the adjacent files. +/// shift() moves a bitboard one step along direction D (mainly for pawns) -inline Bitboard adjacent_files_bb(File f) { - return AdjacentFilesBB[f]; +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; } -/// this_and_adjacent_files_bb takes a file as input and returns a bitboard -/// representing all squares on the given and adjacent files. +/// pawn_attacks_bb() returns the pawn attacks for the given color from the +/// squares in the given bitboard. -inline Bitboard this_and_adjacent_files_bb(File f) { - return ThisAndAdjacentFilesBB[f]; +template +constexpr Bitboard pawn_attacks_bb(Bitboard b) { + return C == WHITE ? shift(b) | shift(b) + : shift(b) | shift(b); } -/// 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. +/// double_pawn_attacks_bb() returns the pawn attacks for the given color +/// from the squares in the given bitboard. -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; +template +constexpr Bitboard double_pawn_attacks_bb(Bitboard b) { + return C == WHITE ? shift(b) & shift(b) + : shift(b) & shift(b); } -inline Bitboard in_front_bb(Color c, Square s) { - return InFrontBB[c][rank_of(s)]; + +/// adjacent_files_bb() returns a bitboard representing all the squares on the +/// adjacent files of the given one. + +inline Bitboard adjacent_files_bb(File f) { + return shift(FileBB[f]) | shift(FileBB[f]); } -/// 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. +/// between_bb() returns a bitboard representing all the squares between the two +/// given ones. 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 rank, file +/// or diagonal, 0 is returned. inline Bitboard between_bb(Square s1, Square s2) { return BetweenBB[s1][s2]; } -/// 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) +/// 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 forward_bb(Color c, Square s) { - return ForwardBB[c][s]; +inline Bitboard forward_ranks_bb(Color c, Square s) { + return ForwardRanksBB[c][rank_of(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) +/// 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: +/// ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s) -inline Bitboard passed_pawn_mask(Color c, Square s) { - return PassedPawnMask[c][s]; +inline Bitboard forward_file_bb(Color c, Square s) { + return ForwardFileBB[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); +/// 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] = forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s)); -inline Bitboard attack_span_mask(Color c, Square s) { - return AttackSpanMask[c][s]; +inline Bitboard pawn_attack_span(Color c, Square s) { + return PawnAttackSpan[c][s]; } -/// squares_aligned returns true if the squares s1, s2 and s3 are aligned -/// either on a straight or on a diagonal line. +/// 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_file_bb(c, s) -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]); +inline Bitboard passed_pawn_mask(Color c, Square s) { + return PassedPawnMask[c][s]; } -/// same_color_squares() returns a bitboard representing all squares with -/// the same color of the given square. +/// aligned() returns true if the squares s1, s2 and s3 are aligned either on a +/// straight or on a diagonal line. -inline Bitboard same_color_squares(Square s) { - return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL - : ~0xAA55AA55AA55AA55ULL; +inline bool aligned(Square s1, Square s2, Square s3) { + return LineBB[s1][s2] & s3; } -/// Functions for computing sliding attack bitboards. Function attacks_bb() takes -/// a square and a bitboard of occupied squares as input, and returns a bitboard -/// representing all squares attacked by Pt (bishop or rook) on the given square. -template -FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) { +/// distance() functions return the distance between x and y, defined as the +/// number of steps for a king in x to reach y. Works with squares, ranks, files. - Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks; - Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics; - unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts; +template inline int distance(T x, T y) { return x < y ? y - x : x - y; } +template<> inline int distance(Square x, Square y) { return SquareDistance[x][y]; } - if (Is64Bit) - return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]); +template inline int distance(T2 x, T2 y); +template<> inline int distance(Square x, Square y) { return distance(file_of(x), file_of(y)); } +template<> inline int distance(Square x, Square y) { return distance(rank_of(x), rank_of(y)); } - unsigned lo = unsigned(occ) & unsigned(Masks[s]); - unsigned hi = unsigned(occ >> 32) & unsigned(Masks[s] >> 32); - return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s]; -} + +/// attacks_bb() returns a bitboard representing all the squares attacked by a +/// piece of type Pt (bishop or rook) placed on 's'. template -inline Bitboard attacks_bb(Square s, Bitboard occ) { - return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index(s, occ)]; +inline Bitboard attacks_bb(Square s, Bitboard 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) { -/// 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. + assert(pt != PAWN); -#if defined(USE_BSFQ) + switch (pt) + { + case BISHOP: 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 PseudoAttacks[pt][s]; + } +} -# if defined(_MSC_VER) && !defined(__INTEL_COMPILER) -FORCE_INLINE Square lsb(Bitboard b) { - unsigned long index; - _BitScanForward64(&index, b); - return (Square) index; -} +/// 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); -FORCE_INLINE Square msb(Bitboard b) { - unsigned long index; - _BitScanReverse64(&index, b); - return (Square) index; +#endif } -# elif defined(__arm__) -FORCE_INLINE int lsb32(uint32_t v) { - __asm__("rbit %0, %1" : "=r"(v) : "r"(v)); - return __builtin_clz(v); +/// lsb() and msb() return the least/most significant bit in a non-zero bitboard + +#if defined(__GNUC__) // GCC, Clang, ICC + +inline Square lsb(Bitboard b) { + assert(b); + return Square(__builtin_ctzll(b)); } -FORCE_INLINE Square msb(Bitboard b) { - return (Square) (63 - __builtin_clzll(b)); +inline Square msb(Bitboard b) { + assert(b); + return Square(63 ^ __builtin_clzll(b)); } -FORCE_INLINE Square lsb(Bitboard b) { - return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32))); +#elif defined(_MSC_VER) // MSVC + +#ifdef _WIN64 // MSVC, WIN64 + +inline Square lsb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanForward64(&idx, b); + return (Square) idx; } -# else +inline Square msb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanReverse64(&idx, b); + return (Square) idx; +} + +#else // MSVC, WIN32 -FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen - Bitboard index; - __asm__("bsfq %1, %0": "=r"(index): "rm"(b) ); - return (Square) index; +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); + } } -FORCE_INLINE Square msb(Bitboard b) { - Bitboard index; - __asm__("bsrq %1, %0": "=r"(index): "rm"(b) ); - return (Square) index; +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 +#endif + +#else // Compiler is neither GCC nor MSVC compatible + +#error "Compiler not supported." + +#endif + -FORCE_INLINE Square pop_lsb(Bitboard* b) { +/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard + +inline Square pop_lsb(Bitboard* b) { const Square s = lsb(*b); *b &= *b - 1; return s; } -#else // if !defined(USE_BSFQ) -extern Square msb(Bitboard b); -extern Square lsb(Bitboard b); -extern Square pop_lsb(Bitboard* b); +/// frontmost_sq() and backmost_sq() return the square corresponding to the +/// most/least advanced bit relative to the given color. -#endif +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 // !defined(BITBOARD_H_INCLUDED) +#endif // #ifndef BITBOARD_H_INCLUDED