X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=7dbd5329be82abe8caaf5f07b163f8e4234b3a40;hp=3d629de1abe986d63cbf3801f7d1a421cb8006ed;hb=HEAD;hpb=f0f6da2d30fc005fd0fa126ee1eefd11fe10a604 diff --git a/src/bitboard.h b/src/bitboard.h index 3d629de1..7dbd5329 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -1,8 +1,6 @@ /* 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 + 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 @@ -21,26 +19,23 @@ #ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include +#include +#include +#include +#include #include #include "types.h" -namespace Bitbases { - -void init(); -bool probe(Square wksq, Square wpsq, Square bksq, Color us); - -} +namespace Stockfish { namespace Bitboards { -void init(); -const std::string pretty(Bitboard b); - -} +void init(); +std::string pretty(Bitboard b); -constexpr Bitboard AllSquares = ~Bitboard(0); -constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; +} // namespace Stockfish::Bitboards constexpr Bitboard FileABB = 0x0101010101010101ULL; constexpr Bitboard FileBBB = FileABB << 1; @@ -60,330 +55,320 @@ 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]; +extern uint8_t PopCnt16[1 << 16]; +extern uint8_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 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 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 +// Magic holds all magic bitboards relevant data for a single square struct Magic { - Bitboard mask; - Bitboard magic; - Bitboard* attacks; - unsigned shift; + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; - // Compute the attack's index using the 'magic bitboards' approach - unsigned index(Bitboard occupied) const { + // Compute the attack's index using the 'magic bitboards' approach + unsigned index(Bitboard occupied) const { - if (HasPext) - return unsigned(pext(occupied, mask)); + if (HasPext) + return unsigned(pext(occupied, mask)); - if (Is64Bit) - return unsigned(((occupied & mask) * magic) >> shift); + 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; - } + 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) { - return b & SquareBB[s]; +inline Bitboard square_bb(Square s) { + assert(is_ok(s)); + return (1ULL << s); } -inline Bitboard operator|(Bitboard b, Square s) { - return b | SquareBB[s]; -} -inline Bitboard operator^(Bitboard b, Square s) { - return b ^ SquareBB[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. -inline Bitboard& operator|=(Bitboard& b, Square s) { - return b |= SquareBB[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^=(Bitboard& b, Square s) { return b ^= square_bb(s); } -inline Bitboard& operator^=(Bitboard& b, Square s) { - return b ^= SquareBB[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; } -constexpr bool more_than_one(Bitboard b) { - return b & (b - 1); -} +inline Bitboard operator|(Square s1, Square s2) { return square_bb(s1) | s2; } -/// rank_bb() and file_bb() return a bitboard representing all the squares on -/// the given file or rank. +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } -inline Bitboard rank_bb(Rank r) { - return RankBB[r]; -} -inline Bitboard rank_bb(Square s) { - return RankBB[rank_of(s)]; -} +// rank_bb() and file_bb() return a bitboard representing all the squares on +// the given file or rank. -inline Bitboard file_bb(File f) { - return FileBB[f]; -} +constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); } -inline Bitboard file_bb(Square s) { - return FileBB[file_of(s)]; -} +constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); } +constexpr Bitboard file_bb(File f) { return FileABB << f; } -/// make_bitboard() returns a bitboard from a list of squares +constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); } -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) +// 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 == 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. - + 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; +} + + +// 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); + return C == WHITE ? shift(b) | shift(b) + : shift(b) | shift(b); } +inline Bitboard pawn_attacks_bb(Color c, Square 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 AdjacentFilesBB[f]; + assert(is_ok(s)); + return PawnAttacks[c][s]; } +// 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) { -/// 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. + assert(is_ok(s1) && is_ok(s2)); -inline Bitboard between_bb(Square s1, Square s2) { - return BetweenBB[s1][s2]; + return LineBB[s1][s2]; } -/// 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_ranks_bb(Color c, Square s) { - return ForwardRanksBB[c][rank_of(s)]; -} - +// 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) { -/// 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) + assert(is_ok(s1) && is_ok(s2)); -inline Bitboard forward_file_bb(Color c, Square s) { - return ForwardFileBB[c][s]; + 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; } -/// 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 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); -/// 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 Bitboard passed_pawn_mask(Color c, Square s) { - return PassedPawnMask[c][s]; +template<> +inline int distance(Square x, Square y) { + return std::abs(file_of(x) - file_of(y)); } - -/// aligned() 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 LineBB[s1][s2] & s3; +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]; +} -/// 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. +inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } -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]; } +// Returns the pseudo attacks of the given piece type +// assuming an empty board. +template +inline Bitboard attacks_bb(Square 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)); } + assert((Pt != PAWN) && (is_ok(s))); + return PseudoAttacks[Pt][s]; +} -/// attacks_bb() returns a bitboard representing all the squares attacked by a -/// piece of type Pt (bishop or rook) placed on 's'. +// 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) { - const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; - return m.attacks[m.index(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]; + } } +// 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); + assert((pt != PAWN) && (is_ok(s))); - 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]; - } + 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]; + } } -/// popcount() counts the number of non-zero bits in a bitboard - +// 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]]; + 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) +#elif defined(_MSC_VER) - return (int)_mm_popcnt_u64(b); + return int(_mm_popcnt_u64(b)); -#else // Assumed gcc or compatible compiler +#else // Assumed gcc or compatible compiler - return __builtin_popcountll(b); + return __builtin_popcountll(b); #endif } - -/// lsb() and msb() return the least/most significant bit in a non-zero bitboard - -#if defined(__GNUC__) // GCC, Clang, ICC - +// Returns the least significant bit in a non-zero bitboard. 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)); -} + assert(b); -#elif defined(_MSC_VER) // MSVC +#if defined(__GNUC__) // GCC, Clang, ICX -#ifdef _WIN64 // MSVC, WIN64 + return Square(__builtin_ctzll(b)); -inline Square lsb(Bitboard b) { - assert(b); - unsigned long idx; - _BitScanForward64(&idx, b); - return (Square) idx; -} +#elif defined(_MSC_VER) + #ifdef _WIN64 // MSVC, WIN64 -inline Square msb(Bitboard b) { - assert(b); - unsigned long idx; - _BitScanReverse64(&idx, b); - return (Square) idx; -} + unsigned long idx; + _BitScanForward64(&idx, b); + return Square(idx); -#else // MSVC, WIN32 + #else // MSVC, WIN32 + unsigned long idx; -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); - } + if (b & 0xffffffff) + { + _BitScanForward(&idx, int32_t(b)); + return Square(idx); + } + else + { + _BitScanForward(&idx, int32_t(b >> 32)); + return Square(idx + 32); + } + #endif +#else // Compiler is neither GCC nor MSVC compatible + #error "Compiler not supported." +#endif } +// Returns the most significant bit in a non-zero bitboard. 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); - } -} + assert(b); -#endif +#if defined(__GNUC__) // GCC, Clang, ICX -#else // Compiler is neither GCC nor MSVC compatible + return Square(63 ^ __builtin_clzll(b)); -#error "Compiler not supported." +#elif defined(_MSC_VER) + #ifdef _WIN64 // MSVC, WIN64 -#endif + unsigned long idx; + _BitScanReverse64(&idx, b); + return Square(idx); + #else // MSVC, WIN32 -/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard + unsigned long idx; -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); + } + #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; +} -/// frontmost_sq() and backmost_sq() return the square corresponding to the -/// most/least advanced bit relative to the given color. +// 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