X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitboard.h;h=03a511361f49d643ae6fdad8e0fbea7d6e3f1e0a;hb=2d0237db3f0e596fb06e3ffbadba84dcc4e018f6;hp=f361658ae73e54c835fafe3839066c4d1c12e46a;hpb=fbb53524efd94c4b227c72c725c628a4aa5f9f72;p=stockfish diff --git a/src/bitboard.h b/src/bitboard.h index f361658a..03a51136 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -1,14 +1,12 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file) 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 @@ -21,316 +19,366 @@ #ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include +#include +#include +#include +#include #include #include "types.h" +namespace Stockfish { + namespace Bitboards { -void init(); -const std::string pretty(Bitboard b); +void init(); +std::string pretty(Bitboard b); -} +} // namespace Stockfish::Bitboards -namespace Bitbases { +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; -void init_kpk(); -bool probe_kpk(Square wksq, Square wpsq, Square bksq, Color us); +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 uint8_t PopCnt16[1 << 16]; +extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB]; -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); - -extern Bitboard RookMasks[SQUARE_NB]; -extern Bitboard RookMagics[SQUARE_NB]; -extern Bitboard* RookAttacks[SQUARE_NB]; -extern unsigned RookShifts[SQUARE_NB]; - -extern Bitboard BishopMasks[SQUARE_NB]; -extern Bitboard BishopMagics[SQUARE_NB]; -extern Bitboard* BishopAttacks[SQUARE_NB]; -extern unsigned BishopShifts[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 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 PawnAttackSpan[COLOR_NB][SQUARE_NB]; extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; -extern int SquareDistance[SQUARE_NB][SQUARE_NB]; -const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; +// Magic holds all magic bitboards relevant data for a single square +struct Magic { + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; -/// 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. + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { -inline Bitboard operator&(Bitboard b, Square s) { - return b & SquareBB[s]; -} + if (HasPext) + return unsigned(pext(occupied, mask)); -inline Bitboard& operator|=(Bitboard& b, Square s) { - return b |= SquareBB[s]; -} + if (Is64Bit) + return unsigned(((occupied & mask) * magic) >> shift); -inline Bitboard& operator^=(Bitboard& b, Square s) { - return b ^= SquareBB[s]; -} + unsigned lo = unsigned(occupied) & unsigned(mask); + unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32); + return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift; + } +}; -inline Bitboard operator|(Bitboard b, Square s) { - return b | SquareBB[s]; -} +extern Magic RookMagics[SQUARE_NB]; +extern Magic BishopMagics[SQUARE_NB]; -inline Bitboard operator^(Bitboard b, Square s) { - return b ^ SquareBB[s]; +inline Bitboard square_bb(Square s) { + assert(is_ok(s)); + return (1ULL << s); } -inline bool more_than_one(Bitboard b) { - return b & (b - 1); -} -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]; } +// 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. -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)); } +inline Bitboard operator&(Bitboard b, Square s) { return b & square_bb(s); } +inline Bitboard operator|(Bitboard b, Square s) { return b | square_bb(s); } +inline Bitboard operator^(Bitboard b, Square s) { return b ^ square_bb(s); } +inline Bitboard& operator|=(Bitboard& b, Square s) { return b |= square_bb(s); } +inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= square_bb(s); } +inline Bitboard operator&(Square s, Bitboard b) { return b & s; } +inline Bitboard operator|(Square s, Bitboard b) { return b | s; } +inline Bitboard operator^(Square s, Bitboard b) { return b ^ s; } -/// shift_bb() moves bitboard one step along direction Delta. Mainly for pawns. +inline Bitboard operator|(Square s1, Square s2) { return square_bb(s1) | s2; } -template -inline Bitboard shift_bb(Bitboard b) { +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } - 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() return a bitboard representing all the squares on +// the given file or rank. -/// 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. +constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); } -inline Bitboard rank_bb(Rank r) { - return RankBB[r]; -} +constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); } -inline Bitboard rank_bb(Square s) { - return RankBB[rank_of(s)]; -} +constexpr Bitboard file_bb(File f) { return FileABB << f; } -inline Bitboard file_bb(File f) { - return FileBB[f]; -} +constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); } + + +// shift() moves a bitboard one or two steps as specified by the direction D -inline Bitboard file_bb(Square s) { - return FileBB[file_of(s)]; +template +constexpr Bitboard shift(Bitboard b) { + return D == NORTH ? b << 8 + : D == SOUTH ? b >> 8 + : D == NORTH + NORTH ? b << 16 + : D == SOUTH + SOUTH ? b >> 16 + : 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; } -/// adjacent_files_bb() takes a file as input and returns a bitboard representing -/// all squares on the adjacent files. +// pawn_attacks_bb() returns the squares attacked by pawns of the given color +// from the squares in the given bitboard. -inline Bitboard adjacent_files_bb(File f) { - return AdjacentFilesBB[f]; +template +constexpr Bitboard pawn_attacks_bb(Bitboard b) { + return C == WHITE ? shift(b) | shift(b) + : shift(b) | shift(b); } +inline Bitboard pawn_attacks_bb(Color c, Square s) { -/// 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]; + assert(is_ok(s)); + return PawnAttacks[c][s]; } +// line_bb() returns a bitboard representing an entire line (from board edge +// to board edge) that intersects the two given squares. If the given squares +// are not on a same file/rank/diagonal, the function returns 0. For instance, +// line_bb(SQ_C4, SQ_F7) will return a bitboard with the A2-G8 diagonal. -/// 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 rank, file or diagonal, -/// 0 is returned. +inline Bitboard line_bb(Square s1, Square s2) { -inline Bitboard between_bb(Square s1, Square s2) { - return BetweenBB[s1][s2]; + assert(is_ok(s1) && is_ok(s2)); + + return LineBB[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) +// between_bb(s1, s2) returns a bitboard representing the squares in the semi-open +// segment between the squares s1 and s2 (excluding s1 but including s2). If the +// given squares are not on a same file/rank/diagonal, it returns s2. For instance, +// between_bb(SQ_C4, SQ_F7) will return a bitboard with squares D5, E6 and F7, but +// between_bb(SQ_E6, SQ_F8) will return a bitboard with the square F8. This trick +// allows to generate non-king evasion moves faster: the defending piece must either +// interpose itself to cover the check or capture the checking piece. -inline Bitboard forward_bb(Color c, Square s) { - return ForwardBB[c][s]; +inline Bitboard between_bb(Square s1, Square s2) { + + assert(is_ok(s1) && is_ok(s2)); + + return BetweenBB[s1][s2]; } +// aligned() returns true if the squares s1, s2 and s3 are aligned either on a +// straight or on a diagonal line. -/// 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 bool aligned(Square s1, Square s2, Square s3) { return line_bb(s1, s2) & s3; } -inline Bitboard pawn_attack_span(Color c, Square s) { - return PawnAttackSpan[c][s]; + +// distance() functions return the distance between x and y, defined as the +// number of steps for a king in x to reach y. + +template +inline int distance(Square x, Square y); +template<> +inline int distance(Square x, Square y) { + return std::abs(file_of(x) - file_of(y)); +} +template<> +inline int distance(Square x, Square y) { + return std::abs(rank_of(x) - rank_of(y)); } +template<> +inline int distance(Square x, Square y) { + return SquareDistance[x][y]; +} + +inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } + +// attacks_bb(Square) returns the pseudo attacks of the given piece type +// assuming an empty board. +template +inline Bitboard attacks_bb(Square 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] = pawn_attack_span(c, s) | forward_bb(c, s) + assert((Pt != PAWN) && (is_ok(s))); -inline Bitboard passed_pawn_mask(Color c, Square s) { - return PassedPawnMask[c][s]; + return PseudoAttacks[Pt][s]; } -/// squares_of_color() returns a bitboard representing all squares with the same -/// color of the given square. +// attacks_bb(Square, Bitboard) returns the attacks by the given piece +// assuming the board is occupied according to the passed Bitboard. +// Sliding piece attacks do not continue passed an occupied square. + +template +inline Bitboard attacks_bb(Square s, Bitboard occupied) { + + assert((Pt != PAWN) && (is_ok(s))); -inline Bitboard squares_of_color(Square s) { - return DarkSquares & s ? DarkSquares : ~DarkSquares; + switch (Pt) + { + case BISHOP : + return BishopMagics[s].attacks[BishopMagics[s].index(occupied)]; + case ROOK : + return RookMagics[s].attacks[RookMagics[s].index(occupied)]; + case QUEEN : + return attacks_bb(s, occupied) | attacks_bb(s, occupied); + default : + return PseudoAttacks[Pt][s]; + } } +inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { -/// aligned() returns true if the squares s1, s2 and s3 are aligned -/// either on a straight or on a diagonal line. + assert((pt != PAWN) && (is_ok(s))); -inline bool aligned(Square s1, Square s2, Square s3) { - return LineBB[s1][s2] & s3; + switch (pt) + { + case BISHOP : + return attacks_bb(s, occupied); + case ROOK : + return attacks_bb(s, occupied); + case QUEEN : + return attacks_bb(s, occupied) | attacks_bb(s, occupied); + default : + return PseudoAttacks[pt][s]; + } } -/// 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 occupied) { +// popcount() counts the number of non-zero bits in a bitboard - Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks; - Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics; - unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts; +inline int popcount(Bitboard b) { - if (HasPext) - return unsigned(_pext_u64(occupied, Masks[s])); +#ifndef USE_POPCNT - if (Is64Bit) - return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]); + 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]]; - 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]; -} +#elif defined(_MSC_VER) -template -inline Bitboard attacks_bb(Square s, Bitboard occupied) { - return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index(s, occupied)]; -} + return int(_mm_popcnt_u64(b)); + +#else // Assumed gcc or compatible compiler -inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) { + return __builtin_popcountll(b); - switch (type_of(pc)) - { - case BISHOP: return attacks_bb(s, occupied); - case ROOK : return attacks_bb(s, occupied); - case QUEEN : return attacks_bb(s, occupied) | attacks_bb(s, occupied); - default : return StepAttacksBB[pc][s]; - } +#endif } -/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard. -/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard. -#ifdef USE_BSFQ +// lsb() and msb() return the least/most significant bit in a non-zero bitboard -# if defined(_MSC_VER) && !defined(__INTEL_COMPILER) +#if defined(__GNUC__) // GCC, Clang, ICX -FORCE_INLINE Square lsb(Bitboard b) { - unsigned long idx; - _BitScanForward64(&idx, b); - return (Square) idx; +inline Square lsb(Bitboard b) { + assert(b); + return Square(__builtin_ctzll(b)); } -FORCE_INLINE Square msb(Bitboard b) { - unsigned long idx; - _BitScanReverse64(&idx, b); - return (Square) idx; +inline Square msb(Bitboard b) { + assert(b); + return Square(63 ^ __builtin_clzll(b)); } -# elif defined(__arm__) +#elif defined(_MSC_VER) // MSVC -FORCE_INLINE int lsb32(uint32_t v) { - __asm__("rbit %0, %1" : "=r"(v) : "r"(v)); - return __builtin_clz(v); -} + #ifdef _WIN64 // MSVC, WIN64 -FORCE_INLINE Square msb(Bitboard b) { - return (Square) (63 - __builtin_clzll(b)); +inline Square lsb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanForward64(&idx, b); + return (Square) idx; } -FORCE_INLINE Square lsb(Bitboard b) { - return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32))); +inline Square msb(Bitboard b) { + assert(b); + unsigned long idx; + _BitScanReverse64(&idx, b); + return (Square) idx; } -# else + #else // MSVC, WIN32 -FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen - Bitboard idx; - __asm__("bsfq %1, %0": "=r"(idx): "rm"(b) ); - return (Square) idx; -} +inline Square lsb(Bitboard b) { + assert(b); + unsigned long idx; -FORCE_INLINE Square msb(Bitboard b) { - Bitboard idx; - __asm__("bsrq %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); + } } -# endif +inline Square msb(Bitboard b) { + assert(b); + unsigned long idx; -FORCE_INLINE Square pop_lsb(Bitboard* b) { - const Square s = lsb(*b); - *b &= *b - 1; - return s; + if (b >> 32) + { + _BitScanReverse(&idx, int32_t(b >> 32)); + return Square(idx + 32); + } + else + { + _BitScanReverse(&idx, int32_t(b)); + return Square(idx); + } } -#else // if defined(USE_BSFQ) + #endif + +#else // Compiler is neither GCC nor MSVC compatible -extern Square msb(Bitboard b); -extern Square lsb(Bitboard b); -extern Square pop_lsb(Bitboard* b); + #error "Compiler not supported." #endif -/// frontmost_sq() and backmost_sq() find the square corresponding to the -/// most/least advanced bit relative to the given color. +// least_significant_square_bb() returns the bitboard of the least significant +// square of a non-zero bitboard. It is equivalent to square_bb(lsb(bb)). + +inline Bitboard least_significant_square_bb(Bitboard b) { + assert(b); + return b & -b; +} + +// pop_lsb() finds and clears the least significant bit in a non-zero bitboard + +inline Square pop_lsb(Bitboard& b) { + assert(b); + const Square s = lsb(b); + b &= b - 1; + return s; +} -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); } +} // namespace Stockfish -#endif // #ifndef BITBOARD_H_INCLUDED +#endif // #ifndef BITBOARD_H_INCLUDED