X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=ba1b0072bce5079064b5f59cbe26328cb7b6dc03;hp=77a824ba62106965ba9513803a19c650c092bb4c;hb=28b6a457c24d9202ba43a6d6703221250f0f8749;hpb=f256388e0808b45d8468b088cdc141a41feac3fb diff --git a/src/bitboard.h b/src/bitboard.h index 77a824ba..ba1b0072 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -2,7 +2,7 @@ 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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2017 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 @@ -39,6 +39,7 @@ const std::string pretty(Bitboard b); } +const Bitboard AllSquares = ~Bitboard(0); const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; const Bitboard FileABB = 0x0101010101010101ULL; @@ -61,29 +62,45 @@ const Bitboard Rank8BB = Rank1BB << (8 * 7); extern int SquareDistance[SQUARE_NB][SQUARE_NB]; -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 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 ForwardBB[COLOR_NB][SQUARE_NB]; +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 +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 @@ -109,7 +126,7 @@ inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= SquareBB[s]; } -inline bool more_than_one(Bitboard b) { +constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } @@ -134,13 +151,13 @@ inline Bitboard file_bb(Square s) { } -/// shift_bb() moves a bitboard one step along direction Delta. Mainly for pawns +/// shift() moves a bitboard one step along direction D. Mainly for pawns -template -inline Bitboard shift_bb(Bitboard b) { - 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 +template +constexpr 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; } @@ -163,28 +180,28 @@ inline Bitboard between_bb(Square s1, Square s2) { } -/// in_front_bb() returns a bitboard representing all the squares on all the ranks +/// forward_ranks_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. +/// instance, forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2. -inline Bitboard in_front_bb(Color c, Rank r) { - return InFrontBB[c][r]; +inline Bitboard forward_ranks_bb(Color c, Square s) { + return ForwardRanksBB[c][rank_of(s)]; } -/// forward_bb() returns a bitboard representing all the squares along the line +/// 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: -/// ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s) +/// ForwardFileBB[c][s] = forward_ranks_bb(c, s) & file_bb(s) -inline Bitboard forward_bb(Color c, Square s) { - return ForwardBB[c][s]; +inline Bitboard forward_file_bb(Color c, Square s) { + return ForwardFileBB[c][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] = in_front_bb(c, s) & adjacent_files_bb(s); +/// 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]; @@ -193,7 +210,7 @@ inline Bitboard pawn_attack_span(Color c, Square s) { /// 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) +/// 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]; @@ -220,43 +237,51 @@ template<> inline int distance(Square x, Square y) { return distance(rank_ /// 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) { - - Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks; - Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics; - unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts; - - if (HasPext) - return unsigned(pext(occupied, Masks[s])); - - if (Is64Bit) - return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[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]; -} +/// piece of type Pt (bishop or rook) placed on 's'. template inline Bitboard attacks_bb(Square s, Bitboard occupied) { - return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index(s, occupied)]; + + const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; + return m.attacks[m.index(occupied)]; } -inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) { +inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { - switch (type_of(pc)) + assert(pt != PAWN); + + switch (pt) { case BISHOP: return attacks_bb(s, occupied); - case ROOK : 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 StepAttacksBB[pc][s]; + default : return PseudoAttacks[pt][s]; } } +/// 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); + +#endif +} + + /// lsb() and msb() return the least/most significant bit in a non-zero bitboard #if defined(__GNUC__) @@ -268,7 +293,7 @@ inline Square lsb(Bitboard b) { inline Square msb(Bitboard b) { assert(b); - return Square(63 - __builtin_clzll(b)); + return Square(63 ^ __builtin_clzll(b)); } #elif defined(_WIN64) && defined(_MSC_VER)