X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=7dbd5329be82abe8caaf5f07b163f8e4234b3a40;hp=bef6467560bc7efcb122514954686ea5c61b3e93;hb=HEAD;hpb=9f8f093fd63f612ff28ca8b4812d0701f6d64ea7 diff --git a/src/bitboard.h b/src/bitboard.h index bef64675..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) 2015-2017 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 @@ -21,318 +19,356 @@ #ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include +#include +#include +#include +#include #include #include "types.h" -namespace Bitbases { +namespace Stockfish { -void init(); -bool probe(Square wksq, Square wpsq, Square bksq, Color us); +namespace Bitboards { -} +void init(); +std::string pretty(Bitboard b); -namespace Bitboards { +} // namespace Stockfish::Bitboards -void init(); -const std::string pretty(Bitboard b); +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; -} +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 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); - -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 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 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]; -/// 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. +// Magic holds all magic bitboards relevant data for a single square +struct Magic { + Bitboard mask; + Bitboard magic; + Bitboard* attacks; + unsigned shift; -inline Bitboard operator&(Bitboard b, Square s) { - return b & SquareBB[s]; -} + // 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 bool more_than_one(Bitboard b) { - return b & (b - 1); +inline Bitboard square_bb(Square s) { + assert(is_ok(s)); + return (1ULL << s); } -/// 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]; -} +// 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 rank_bb(Square s) { - return RankBB[rank_of(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 file_bb(File f) { - return FileBB[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 file_bb(Square s) { - return FileBB[file_of(s)]; -} +inline Bitboard operator|(Square s1, Square s2) { return square_bb(s1) | s2; } +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } -/// shift() moves a bitboard one step along direction D. Mainly for pawns -template -inline Bitboard shift(Bitboard b) { - return D == NORTH ? b << 8 : D == SOUTH ? b >> 8 - : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 - : D == NORTH_WEST ? (b & ~FileABB) << 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9 - : 0; -} +// rank_bb() and file_bb() return a bitboard representing all the squares on +// the given file or rank. +constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); } -/// adjacent_files_bb() returns a bitboard representing all the squares on the -/// adjacent files of the given one. +constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); } -inline Bitboard adjacent_files_bb(File f) { - return AdjacentFilesBB[f]; -} +constexpr Bitboard file_bb(File f) { return FileABB << f; } +constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); } -/// 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]; +// 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; } -/// 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. - -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; +// 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 pawn_attacks_bb(Color c, Square s) { -/// forward_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, rank_of(s)) & file_bb(s) - -inline Bitboard forward_bb(Color c, Square s) { - return ForwardBB[c][s]; + 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) { -/// 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, rank_of(s)) & adjacent_files_bb(s); + assert(is_ok(s1) && is_ok(s2)); -inline Bitboard pawn_attack_span(Color c, Square s) { - return PawnAttackSpan[c][s]; + return LineBB[s1][s2]; } -/// 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) - -inline Bitboard passed_pawn_mask(Color c, Square s) { - return PassedPawnMask[c][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) { -/// aligned() returns true if the squares s1, s2 and s3 are aligned either on a -/// straight or on a diagonal line. + assert(is_ok(s1) && is_ok(s2)); -inline bool aligned(Square s1, Square s2, Square s3) { - return LineBB[s1][s2] & s3; + 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; } -/// 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. -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]; } +// 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(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)); } +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)); +} -/// 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) { +template<> +inline int distance(Square x, Square y) { + return std::abs(rank_of(x) - rank_of(y)); +} - extern Bitboard RookMasks[SQUARE_NB]; - extern Bitboard RookMagics[SQUARE_NB]; - extern unsigned RookShifts[SQUARE_NB]; - extern Bitboard BishopMasks[SQUARE_NB]; - extern Bitboard BishopMagics[SQUARE_NB]; - extern unsigned BishopShifts[SQUARE_NB]; +template<> +inline int distance(Square x, Square y) { + return SquareDistance[x][y]; +} - Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks; - Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics; - unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts; +inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } - if (HasPext) - return unsigned(pext(occupied, Masks[s])); +// Returns the pseudo attacks of the given piece type +// assuming an empty board. +template +inline Bitboard attacks_bb(Square s) { - if (Is64Bit) - return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]); + assert((Pt != PAWN) && (is_ok(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]; + 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. template inline Bitboard attacks_bb(Square s, Bitboard occupied) { - extern Bitboard* RookAttacks[SQUARE_NB]; - extern Bitboard* BishopAttacks[SQUARE_NB]; - - return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index(s, 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 Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) { - - 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]; - } +// 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]; + } } -/// 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__) - +// Returns the least significant bit in a non-zero bitboard. inline Square lsb(Bitboard b) { - assert(b); - return Square(__builtin_ctzll(b)); + assert(b); + +#if defined(__GNUC__) // GCC, Clang, ICX + + return Square(__builtin_ctzll(b)); + +#elif defined(_MSC_VER) + #ifdef _WIN64 // MSVC, WIN64 + + unsigned long idx; + _BitScanForward64(&idx, b); + return Square(idx); + + #else // MSVC, WIN32 + 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); + } + #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); - return Square(63 ^ __builtin_clzll(b)); -} + assert(b); -#elif defined(_WIN64) && defined(_MSC_VER) +#if defined(__GNUC__) // GCC, Clang, ICX -inline Square lsb(Bitboard b) { - assert(b); - unsigned long idx; - _BitScanForward64(&idx, b); - return (Square) idx; -} + return Square(63 ^ __builtin_clzll(b)); -inline Square msb(Bitboard b) { - assert(b); - unsigned long idx; - _BitScanReverse64(&idx, b); - return (Square) idx; -} +#elif defined(_MSC_VER) + #ifdef _WIN64 // MSVC, WIN64 -#else + unsigned long idx; + _BitScanReverse64(&idx, b); + return Square(idx); -#define NO_BSF // Fallback on software implementation for other cases + #else // MSVC, WIN32 -Square lsb(Bitboard b); -Square msb(Bitboard 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 +#else // Compiler is neither GCC nor MSVC compatible + #error "Compiler not supported." #endif - - -/// 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; } +// 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