X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitboard.h;h=390966e3494273969bdb53a50c6953a6c9782611;hb=HEAD;hp=404178dcc4b73f2c7e564b173c637c3d29ba29b9;hpb=6d665b7f78d03ef7c15d7964b28dccd6b6826adf;p=stockfish diff --git a/src/bitboard.h b/src/bitboard.h index 404178dc..7dbd5329 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) 2008-2010 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 @@ -18,274 +16,359 @@ along with this program. If not, see . */ -#if !defined(BITBOARD_H_INCLUDED) +#ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include +#include +#include +#include +#include +#include + #include "types.h" -const Bitboard EmptyBoardBB = 0; - -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 SquaresByColorBB[2]; -extern Bitboard FileBB[8]; -extern Bitboard NeighboringFilesBB[8]; -extern Bitboard ThisAndNeighboringFilesBB[8]; -extern Bitboard RankBB[8]; -extern Bitboard InFrontBB[2][8]; - -extern Bitboard SetMaskBB[65]; -extern Bitboard ClearMaskBB[65]; - -extern Bitboard StepAttacksBB[16][64]; -extern Bitboard BetweenBB[64][64]; - -extern Bitboard SquaresInFrontMask[2][64]; -extern Bitboard PassedPawnMask[2][64]; -extern Bitboard AttackSpanMask[2][64]; - -extern const uint64_t RMult[64]; -extern int RShift[64]; -extern Bitboard RMask[64]; -extern Bitboard* RAttacks[64]; - -extern const uint64_t BMult[64]; -extern int BShift[64]; -extern Bitboard BMask[64]; -extern Bitboard* BAttacks[64]; - -extern Bitboard BishopPseudoAttacks[64]; -extern Bitboard RookPseudoAttacks[64]; -extern Bitboard QueenPseudoAttacks[64]; - -extern uint8_t BitCount8Bit[256]; - - -/// Functions for testing whether a given bit is set in a bitboard, and for -/// setting and clearing bits. - -inline Bitboard bit_is_set(Bitboard b, Square s) { - return b & SetMaskBB[s]; -} +namespace Stockfish { -inline void set_bit(Bitboard *b, Square s) { - *b |= SetMaskBB[s]; -} +namespace Bitboards { -inline void clear_bit(Bitboard *b, Square s) { - *b &= ClearMaskBB[s]; -} +void init(); +std::string pretty(Bitboard b); +} // namespace Stockfish::Bitboards -/// Functions used to update a bitboard after a move. This is faster -/// then calling a sequence of clear_bit() + set_bit() +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; -inline Bitboard make_move_bb(Square from, Square to) { - return SetMaskBB[from] | SetMaskBB[to]; -} +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); -inline void do_move_bb(Bitboard *b, Bitboard move_bb) { - *b ^= move_bb; -} +extern uint8_t PopCnt16[1 << 16]; +extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB]; +extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; +extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; +extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; -/// 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. -inline Bitboard rank_bb(Rank r) { - return RankBB[r]; -} +// Magic holds all magic bitboards relevant data for a single square +struct Magic { + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; -inline Bitboard rank_bb(Square s) { - return RankBB[square_rank(s)]; -} + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { -inline Bitboard file_bb(File f) { - return FileBB[f]; -} + if (HasPext) + return unsigned(pext(occupied, mask)); -inline Bitboard file_bb(Square s) { - return FileBB[square_file(s)]; -} + 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; + } +}; -/// neighboring_files_bb takes a file or a square as input and returns a -/// bitboard representing all squares on the neighboring files. +extern Magic RookMagics[SQUARE_NB]; +extern Magic BishopMagics[SQUARE_NB]; -inline Bitboard neighboring_files_bb(File f) { - return NeighboringFilesBB[f]; +inline Bitboard square_bb(Square s) { + assert(is_ok(s)); + return (1ULL << s); } -inline Bitboard neighboring_files_bb(Square s) { - return NeighboringFilesBB[square_file(s)]; -} +// 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. -/// this_and_neighboring_files_bb takes a file or a square as input and returns -/// a bitboard representing all squares on the given and neighboring files. +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 this_and_neighboring_files_bb(File f) { - return ThisAndNeighboringFilesBB[f]; -} +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; } -inline Bitboard this_and_neighboring_files_bb(Square s) { - return ThisAndNeighboringFilesBB[square_file(s)]; -} +inline Bitboard operator|(Square s1, Square s2) { return square_bb(s1) | s2; } +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } -/// 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. -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; -} +// rank_bb() and file_bb() return a bitboard representing all the squares on +// the given file or rank. -inline Bitboard in_front_bb(Color c, Square s) { - return InFrontBB[c][square_rank(s)]; -} +constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); } +constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); } -/// Functions for computing sliding attack bitboards. rook_attacks_bb(), -/// bishop_attacks_bb() and queen_attacks_bb() all take a square and a -/// bitboard of occupied squares as input, and return a bitboard representing -/// all squares attacked by a rook, bishop or queen on the given square. +constexpr Bitboard file_bb(File f) { return FileABB << f; } -#if defined(IS_64BIT) +constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); } -inline Bitboard rook_attacks_bb(Square s, Bitboard occ) { - return RAttacks[s][((occ & RMask[s]) * RMult[s]) >> RShift[s]]; -} -inline Bitboard bishop_attacks_bb(Square s, Bitboard occ) { - return BAttacks[s][((occ & BMask[s]) * BMult[s]) >> BShift[s]]; +// Moves a bitboard one or two steps as specified by the direction D +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; } -#else // if !defined(IS_64BIT) -inline Bitboard rook_attacks_bb(Square s, Bitboard occ) { - Bitboard b = occ & RMask[s]; - return RAttacks[s] - [unsigned(int(b) * int(RMult[s]) ^ int(b >> 32) * int(RMult[s] >> 32)) >> RShift[s]]; +// Returns the squares attacked by pawns of 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); } -inline Bitboard bishop_attacks_bb(Square s, Bitboard occ) { - Bitboard b = occ & BMask[s]; - return BAttacks[s] - [unsigned(int(b) * int(BMult[s]) ^ int(b >> 32) * int(BMult[s] >> 32)) >> BShift[s]]; +inline Bitboard pawn_attacks_bb(Color c, Square s) { + + assert(is_ok(s)); + return PawnAttacks[c][s]; } -#endif +// 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. +inline Bitboard line_bb(Square s1, Square s2) { + + assert(is_ok(s1) && is_ok(s2)); -inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) { - return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers); + return LineBB[s1][s2]; } -/// squares_between returns a bitboard representing all squares between -/// two squares. For instance, squares_between(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, EmptyBoardBB is returned. +// 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 between_bb(Square s1, Square s2) { -inline Bitboard squares_between(Square s1, Square s2) { - return BetweenBB[s1][s2]; + assert(is_ok(s1) && is_ok(s2)); + + return BetweenBB[s1][s2]; } +// Returns true if the squares s1, s2 and s3 are aligned either on a +// straight or on a diagonal line. +inline bool aligned(Square s1, Square s2, Square s3) { return line_bb(s1, s2) & s3; } -/// squares_in_front_of 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: -/// SquaresInFrontOf[c][s] = in_front_bb(c, s) & file_bb(s) -inline Bitboard squares_in_front_of(Color c, Square s) { - return SquaresInFrontMask[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); -/// 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_neighboring_files_bb(s) +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)); +} -inline Bitboard passed_pawn_mask(Color c, Square s) { - return PassedPawnMask[c][s]; +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)); } -/// 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) & neighboring_files_bb(s); +// Returns the pseudo attacks of the given piece type +// assuming an empty board. +template +inline Bitboard attacks_bb(Square s) { -inline Bitboard attack_span_mask(Color c, Square s) { - return AttackSpanMask[c][s]; + assert((Pt != PAWN) && (is_ok(s))); + + return PseudoAttacks[Pt][s]; } -/// squares_aligned returns true if the squares s1, s2 and s3 are aligned -/// either on a straight or on a diagonal line. +// 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))); + + 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 bool squares_aligned(Square s1, Square s2, Square s3) { - return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3]) - & ((1ULL << s1) | (1ULL << s2) | (1ULL << s3)); +// 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. +inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { + + assert((pt != PAWN) && (is_ok(s))); + + 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]; + } } -/// first_1() finds the least significant nonzero bit in a nonzero bitboard. -/// pop_1st_bit() finds and clears the least significant nonzero bit in a -/// nonzero bitboard. +// Counts the number of non-zero bits in a bitboard. +inline int popcount(Bitboard b) { -#if defined(USE_BSFQ) +#ifndef USE_POPCNT -#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) + 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]]; -FORCE_INLINE Square first_1(Bitboard b) { - unsigned long index; - _BitScanForward64(&index, b); - return (Square) index; -} -#else +#elif defined(_MSC_VER) + + return int(_mm_popcnt_u64(b)); + +#else // Assumed gcc or compatible compiler + + return __builtin_popcountll(b); -FORCE_INLINE Square first_1(Bitboard b) { // Assembly code by Heinz van Saanen - Bitboard dummy; - __asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) ); - return (Square) dummy; -} #endif +} -FORCE_INLINE Square pop_1st_bit(Bitboard* b) { - const Square s = first_1(*b); - *b &= ~(1ULL<> 32)); + return Square(idx + 32); + } + #endif +#else // Compiler is neither GCC nor MSVC compatible + #error "Compiler not supported." +#endif } -#else // if !defined(USE_BSFQ) +// Returns the most significant bit in a non-zero bitboard. +inline Square msb(Bitboard b) { + assert(b); + +#if defined(__GNUC__) // GCC, Clang, ICX + + return Square(63 ^ __builtin_clzll(b)); + +#elif defined(_MSC_VER) + #ifdef _WIN64 // MSVC, WIN64 + + unsigned long idx; + _BitScanReverse64(&idx, b); + return Square(idx); -extern Square first_1(Bitboard b); -extern Square pop_1st_bit(Bitboard* b); + #else // MSVC, WIN32 + 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 +#else // Compiler is neither GCC nor MSVC compatible + #error "Compiler not supported." #endif +} +// 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; +} + +// 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; +} -extern void print_bitboard(Bitboard b); -extern void init_bitboards(); +} // namespace Stockfish -#endif // !defined(BITBOARD_H_INCLUDED) +#endif // #ifndef BITBOARD_H_INCLUDED