X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=a377703b5b170dbbed3b99ab07892516fe639cc1;hp=639ef3f06e968d7249c55ff45748577a9e6cfefa;hb=7a1ff6d8ff39bb9e6844d24467899d47e942486f;hpb=0a003d3ba1e3082132606d06159693aaa805a138 diff --git a/src/bitboard.cpp b/src/bitboard.cpp index 639ef3f0..a377703b 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, 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 @@ -28,78 +28,70 @@ CACHE_LINE_ALIGNMENT -Bitboard RMasks[64]; -Bitboard RMagics[64]; -Bitboard* RAttacks[64]; -unsigned RShifts[64]; - -Bitboard BMasks[64]; -Bitboard BMagics[64]; -Bitboard* BAttacks[64]; -unsigned BShifts[64]; - -Bitboard SquareBB[64]; -Bitboard FileBB[8]; -Bitboard RankBB[8]; -Bitboard AdjacentFilesBB[8]; -Bitboard ThisAndAdjacentFilesBB[8]; -Bitboard InFrontBB[2][8]; -Bitboard StepAttacksBB[16][64]; -Bitboard BetweenBB[64][64]; -Bitboard DistanceRingsBB[64][8]; -Bitboard ForwardBB[2][64]; -Bitboard PassedPawnMask[2][64]; -Bitboard AttackSpanMask[2][64]; -Bitboard PseudoAttacks[6][64]; - -int SquareDistance[64][64]; +Bitboard RMasks[SQUARE_NB]; +Bitboard RMagics[SQUARE_NB]; +Bitboard* RAttacks[SQUARE_NB]; +unsigned RShifts[SQUARE_NB]; + +Bitboard BMasks[SQUARE_NB]; +Bitboard BMagics[SQUARE_NB]; +Bitboard* BAttacks[SQUARE_NB]; +unsigned BShifts[SQUARE_NB]; + +Bitboard SquareBB[SQUARE_NB]; +Bitboard FileBB[FILE_NB]; +Bitboard RankBB[RANK_NB]; +Bitboard AdjacentFilesBB[FILE_NB]; +Bitboard InFrontBB[COLOR_NB][RANK_NB]; +Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB]; +Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; +Bitboard DistanceRingsBB[SQUARE_NB][8]; +Bitboard ForwardBB[COLOR_NB][SQUARE_NB]; +Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; +Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; +Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; + +int SquareDistance[SQUARE_NB][SQUARE_NB]; namespace { // De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan - const uint64_t DeBruijn_64 = 0x218A392CD3D5DBFULL; + const uint64_t DeBruijn_64 = 0x3F79D71B4CB0A89ULL; const uint32_t DeBruijn_32 = 0x783A9B23; CACHE_LINE_ALIGNMENT - int BSFTable[64]; int MS1BTable[256]; + Square BSFTable[SQUARE_NB]; Bitboard RTable[0x19000]; // Storage space for rook attacks Bitboard BTable[0x1480]; // Storage space for bishop attacks - uint8_t BitCount8Bit[256]; typedef unsigned (Fn)(Square, Bitboard); void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[], Bitboard masks[], unsigned shifts[], Square deltas[], Fn index); + + FORCE_INLINE unsigned bsf_index(Bitboard b) { + + // Matt Taylor's folding for 32 bit systems, extended to 64 bits by Kim Walisch + b ^= (b - 1); + return Is64Bit ? (b * DeBruijn_64) >> 58 + : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn_32) >> 26; + } } /// lsb()/msb() finds the least/most significant bit in a nonzero bitboard. /// pop_lsb() finds and clears the least significant bit in a nonzero bitboard. -#if !defined(USE_BSFQ) - -Square lsb(Bitboard b) { +#ifndef USE_BSFQ - if (Is64Bit) - return Square(BSFTable[((b & -b) * DeBruijn_64) >> 58]); - - b ^= (b - 1); - uint32_t fold = unsigned(b) ^ unsigned(b >> 32); - return Square(BSFTable[(fold * DeBruijn_32) >> 26]); -} +Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; } Square pop_lsb(Bitboard* b) { Bitboard bb = *b; *b = bb & (bb - 1); - - if (Is64Bit) - return Square(BSFTable[((bb & -bb) * DeBruijn_64) >> 58]); - - bb ^= (bb - 1); - uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32); - return Square(BSFTable[(fold * DeBruijn_32) >> 26]); + return BSFTable[bsf_index(bb)]; } Square msb(Bitboard b) { @@ -127,10 +119,10 @@ Square msb(Bitboard b) { result += 8; } - return Square(result + MS1BTable[b32]); + return (Square)(result + MS1BTable[b32]); } -#endif // !defined(USE_BSFQ) +#endif // ifndef USE_BSFQ /// Bitboards::print() prints a bitboard in an easily readable format to the @@ -140,11 +132,11 @@ void Bitboards::print(Bitboard b) { sync_cout; - for (Rank rank = RANK_8; rank >= RANK_1; rank--) + for (Rank rank = RANK_8; rank >= RANK_1; --rank) { std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; - for (File file = FILE_A; file <= FILE_H; file++) + for (File file = FILE_A; file <= FILE_H; ++file) std::cout << "| " << (b & (file | rank) ? "X " : " "); std::cout << "|\n"; @@ -162,10 +154,10 @@ void Bitboards::init() { while (k < (2 << i)) MS1BTable[k++] = i; - for (Bitboard b = 0; b < 256; b++) - BitCount8Bit[b] = (uint8_t)popcount(b); + for (int i = 0; i < 64; i++) + BSFTable[bsf_index(1ULL << i)] = Square(i); - for (Square s = SQ_A1; s <= SQ_H8; s++) + for (Square s = SQ_A1; s <= SQ_H8; ++s) SquareBB[s] = 1ULL << s; FileBB[FILE_A] = FileABB; @@ -177,50 +169,34 @@ void Bitboards::init() { RankBB[i] = RankBB[i - 1] << 8; } - for (File f = FILE_A; f <= FILE_H; f++) - { + for (File f = FILE_A; f <= FILE_H; ++f) AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); - ThisAndAdjacentFilesBB[f] = FileBB[f] | AdjacentFilesBB[f]; - } - for (Rank r = RANK_1; r < RANK_8; r++) + for (Rank r = RANK_1; r < RANK_8; ++r) InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]); - for (Color c = WHITE; c <= BLACK; c++) - for (Square s = SQ_A1; s <= SQ_H8; s++) + for (Color c = WHITE; c <= BLACK; ++c) + for (Square s = SQ_A1; s <= SQ_H8; ++s) { ForwardBB[c][s] = InFrontBB[c][rank_of(s)] & FileBB[file_of(s)]; - PassedPawnMask[c][s] = InFrontBB[c][rank_of(s)] & ThisAndAdjacentFilesBB[file_of(s)]; - AttackSpanMask[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)]; + PawnAttackSpan[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)]; + PassedPawnMask[c][s] = ForwardBB[c][s] | PawnAttackSpan[c][s]; } - for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) - for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) - SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2)); - - for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) - for (int d = 1; d < 8; d++) - for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) - if (SquareDistance[s1][s2] == d) - DistanceRingsBB[s1][d - 1] |= s2; - - for (int i = 0; i < 64; i++) - if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems + for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) + for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2) { - Bitboard b = 1ULL << i; - b ^= b - 1; - b ^= b >> 32; - BSFTable[(uint32_t)(b * DeBruijn_32) >> 26] = i; + SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2)); + if (s1 != s2) + DistanceRingsBB[s1][SquareDistance[s1][s2] - 1] |= s2; } - else - BSFTable[((1ULL << i) * DeBruijn_64) >> 58] = i; int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 }, {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } }; - for (Color c = WHITE; c <= BLACK; c++) - for (PieceType pt = PAWN; pt <= KING; pt++) - for (Square s = SQ_A1; s <= SQ_H8; s++) + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt = PAWN; pt <= KING; ++pt) + for (Square s = SQ_A1; s <= SQ_H8; ++s) for (int k = 0; steps[pt][k]; k++) { Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]); @@ -235,14 +211,14 @@ void Bitboards::init() { init_magics(RTable, RAttacks, RMagics, RMasks, RShifts, RDeltas, magic_index); init_magics(BTable, BAttacks, BMagics, BMasks, BShifts, BDeltas, magic_index); - for (Square s = SQ_A1; s <= SQ_H8; s++) + for (Square s = SQ_A1; s <= SQ_H8; ++s) { PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] = attacks_bb(s, 0); PseudoAttacks[QUEEN][s] |= PseudoAttacks[ ROOK][s] = attacks_bb< ROOK>(s, 0); } - for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) - for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) + for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) + for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2) if (PseudoAttacks[QUEEN][s1] & s2) { Square delta = (s2 - s1) / square_distance(s1, s2); @@ -305,7 +281,7 @@ namespace { // attacks[s] is a pointer to the beginning of the attacks table for square 's' attacks[SQ_A1] = table; - for (Square s = SQ_A1; s <= SQ_H8; s++) + for (Square s = SQ_A1; s <= SQ_H8; ++s) { // Board edges are not considered in the relevant occupancies edges = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s)); @@ -338,9 +314,9 @@ namespace { // until we find the one that passes the verification test. do { do magics[s] = pick_random(rk, booster); - while (BitCount8Bit[(magics[s] * masks[s]) >> 56] < 6); + while (popcount((magics[s] * masks[s]) >> 56) < 6); - memset(attacks[s], 0, size * sizeof(Bitboard)); + std::memset(attacks[s], 0, size * sizeof(Bitboard)); // A good magic must map every possible occupancy to an index that // looks up the correct sliding attack in the attacks[s] database.