X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=3f855c574e6c0e0cc4377820218559f9bbf331e8;hp=1bae6843df5303d3d7379e335debd7c02946b898;hb=4ede49cd850392f28bc9da9537c111d2c3f0b297;hpb=2f47844c7cb34c7de5b5d41cda10b7d8736a20bc diff --git a/src/bitboard.cpp b/src/bitboard.cpp index 1bae6843..3f855c57 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 @@ -23,42 +23,46 @@ #include "bitboard.h" #include "bitcount.h" +#include "misc.h" #include "rkiss.h" 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 ForwardBB[2][64]; -Bitboard PassedPawnMask[2][64]; -Bitboard AttackSpanMask[2][64]; -Bitboard PseudoAttacks[6][64]; - -uint8_t BitCount8Bit[256]; -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 = 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 @@ -66,42 +70,31 @@ namespace { void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[], Bitboard masks[], unsigned shifts[], Square deltas[], Fn index); -} - -/// 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. -#if defined(IS_64BIT) && !defined(USE_BSFQ) + FORCE_INLINE unsigned bsf_index(Bitboard b) { -Square first_1(Bitboard b) { - return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]); + // 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; + } } -Square pop_1st_bit(Bitboard* b) { - Bitboard bb = *b; - *b &= (*b - 1); - return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]); -} +/// 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. -#elif !defined(USE_BSFQ) +#if !defined(USE_BSFQ) -Square first_1(Bitboard b) { - b ^= (b - 1); - uint32_t fold = unsigned(b) ^ unsigned(b >> 32); - return Square(BSFTable[(fold * 0x783A9B23) >> 26]); -} +Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; } -Square pop_1st_bit(Bitboard* b) { +Square pop_lsb(Bitboard* b) { Bitboard bb = *b; *b = bb & (bb - 1); - bb ^= (bb - 1); - uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32); - return Square(BSFTable[(fold * 0x783A9B23) >> 26]); + return BSFTable[bsf_index(bb)]; } -Square last_1(Bitboard b) { +Square msb(Bitboard b) { unsigned b32; int result = 0; @@ -126,7 +119,7 @@ Square last_1(Bitboard b) { result += 8; } - return Square(result + MS1BTable[b32]); + return (Square)(result + MS1BTable[b32]); } #endif // !defined(USE_BSFQ) @@ -137,16 +130,18 @@ Square last_1(Bitboard b) { void Bitboards::print(Bitboard b) { + sync_cout; + for (Rank rank = RANK_8; rank >= RANK_1; rank--) { std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; for (File file = FILE_A; file <= FILE_H; file++) - std::cout << "| " << ((b & make_square(file, rank)) ? "X " : " "); + std::cout << "| " << (b & (file | rank) ? "X " : " "); std::cout << "|\n"; } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; + std::cout << "+---+---+---+---+---+---+---+---+" << sync_endl; } @@ -159,8 +154,8 @@ 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++) SquareBB[s] = 1ULL << s; @@ -175,10 +170,7 @@ void Bitboards::init() { } 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++) InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]); @@ -187,24 +179,19 @@ void Bitboards::init() { 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 (int i = 0; i < 64; i++) - if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems - { - Bitboard b = 1ULL << i; - b ^= b - 1; - b ^= b >> 32; - BSFTable[(uint32_t)(b * 0x783A9B23) >> 26] = i; - } - else - BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i; + 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; int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 }, {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } }; @@ -265,25 +252,17 @@ namespace { } - Bitboard pick_random(Bitboard mask, RKISS& rk, int booster) { - - Bitboard magic; + Bitboard pick_random(RKISS& rk, int booster) { // Values s1 and s2 are used to rotate the candidate magic of a // quantity known to be the optimal to quickly find the magics. int s1 = booster & 63, s2 = (booster >> 6) & 63; - while (true) - { - magic = rk.rand(); - magic = (magic >> s1) | (magic << (64 - s1)); - magic &= rk.rand(); - magic = (magic >> s2) | (magic << (64 - s2)); - magic &= rk.rand(); - - if (BitCount8Bit[(mask * magic) >> 56] >= 6) - return magic; - } + Bitboard m = rk.rand(); + m = (m >> s1) | (m << (64 - s1)); + m &= rk.rand(); + m = (m >> s2) | (m << (64 - s2)); + return m & rk.rand(); } @@ -336,8 +315,10 @@ namespace { // Find a magic for square 's' picking up an (almost) random number // until we find the one that passes the verification test. do { - magics[s] = pick_random(masks[s], rk, booster); - memset(attacks[s], 0, size * sizeof(Bitboard)); + do magics[s] = pick_random(rk, booster); + while (popcount((magics[s] * masks[s]) >> 56) < 6); + + 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. @@ -350,6 +331,8 @@ namespace { if (attack && attack != reference[i]) break; + assert(reference[i] != 0); + attack = reference[i]; } } while (i != size);