X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=40cdbb21ff956601238b0db0dc72176e5cb081cb;hp=e4e409583bcd4b71ebc0bc853746a7c6b0062f1c;hb=797c960d2004eacbbd19c656f483f070130bb358;hpb=e9296d694c72c2378b71ad29cfff2f2c7b45bb0c diff --git a/src/bitboard.cpp b/src/bitboard.cpp index e4e40958..40cdbb21 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -25,33 +25,30 @@ #include "bitcount.h" #include "rkiss.h" +CACHE_LINE_ALIGNMENT + Bitboard RMasks[64]; Bitboard RMagics[64]; Bitboard* RAttacks[64]; -int RShifts[64]; +unsigned RShifts[64]; Bitboard BMasks[64]; Bitboard BMagics[64]; Bitboard* BAttacks[64]; -int BShifts[64]; - -Bitboard SetMaskBB[65]; -Bitboard ClearMaskBB[65]; +unsigned BShifts[64]; +Bitboard SquareBB[64]; Bitboard FileBB[8]; Bitboard RankBB[8]; -Bitboard NeighboringFilesBB[8]; -Bitboard ThisAndNeighboringFilesBB[8]; +Bitboard AdjacentFilesBB[8]; +Bitboard ThisAndAdjacentFilesBB[8]; Bitboard InFrontBB[2][8]; Bitboard StepAttacksBB[16][64]; Bitboard BetweenBB[64][64]; Bitboard SquaresInFrontMask[2][64]; Bitboard PassedPawnMask[2][64]; Bitboard AttackSpanMask[2][64]; - -Bitboard BishopPseudoAttacks[64]; -Bitboard RookPseudoAttacks[64]; -Bitboard QueenPseudoAttacks[64]; +Bitboard PseudoAttacks[6][64]; uint8_t BitCount8Bit[256]; int SquareDistance[64][64]; @@ -61,31 +58,16 @@ namespace { CACHE_LINE_ALIGNMENT int BSFTable[64]; - Bitboard RookTable[0x19000]; // Storage space for rook attacks - Bitboard BishopTable[0x1480]; // Storage space for bishop attacks - - void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[], - Bitboard masks[], int shifts[]); -} - - -/// print_bitboard() prints a bitboard in an easily readable format to the -/// standard output. This is sometimes useful for debugging. + int MS1BTable[256]; + Bitboard RTable[0x19000]; // Storage space for rook attacks + Bitboard BTable[0x1480]; // Storage space for bishop attacks -void print_bitboard(Bitboard b) { + typedef unsigned (Fn)(Square, Bitboard); - for (Rank r = RANK_8; r >= RANK_1; r--) - { - std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; - for (File f = FILE_A; f <= FILE_H; f++) - std::cout << "| " << (bit_is_set(b, make_square(f, r)) ? "X " : " "); - - std::cout << "|\n"; - } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; + 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. @@ -110,59 +92,78 @@ Square first_1(Bitboard b) { return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } -// Use type-punning -union b_union { - - Bitboard b; - struct { -#if defined (BIGENDIAN) - uint32_t h; - uint32_t l; -#else - uint32_t l; - uint32_t h; -#endif - } dw; -}; - -Square pop_1st_bit(Bitboard* bb) { - - b_union u; - Square ret; - - u.b = *bb; - - if (u.dw.l) - { - ret = Square(BSFTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783A9B23) >> 26]); - u.dw.l &= (u.dw.l - 1); - *bb = u.b; - return ret; - } - ret = Square(BSFTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783A9B23) >> 26]); - u.dw.h &= (u.dw.h - 1); - *bb = u.b; - return ret; +Square pop_1st_bit(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]); +} + +Square last_1(Bitboard b) { + + unsigned b32; + int result = 0; + + if (b > 0xFFFFFFFF) + { + b >>= 32; + result = 32; + } + + b32 = unsigned(b); + + if (b32 > 0xFFFF) + { + b32 >>= 16; + result += 16; + } + + if (b32 > 0xFF) + { + b32 >>= 8; + result += 8; + } + + return Square(result + MS1BTable[b32]); } #endif // !defined(USE_BSFQ) -/// bitboards_init() initializes various bitboard arrays. It is called during +/// Bitboards::print() prints a bitboard in an easily readable format to the +/// standard output. This is sometimes useful for debugging. + +void Bitboards::print(Bitboard b) { + + 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 << "|\n"; + } + std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; +} + + +/// Bitboards::init() initializes various bitboard arrays. It is called during /// program initialization. -void bitboards_init() { +void Bitboards::init() { + + for (int k = 0, i = 0; i < 8; i++) + while (k < (2 << i)) + MS1BTable[k++] = i; for (Bitboard b = 0; b < 256; b++) BitCount8Bit[b] = (uint8_t)popcount(b); for (Square s = SQ_A1; s <= SQ_H8; s++) - { - SetMaskBB[s] = 1ULL << s; - ClearMaskBB[s] = ~SetMaskBB[s]; - } - - ClearMaskBB[SQ_NONE] = ~0ULL; + SquareBB[s] = 1ULL << s; FileBB[FILE_A] = FileABB; RankBB[RANK_1] = Rank1BB; @@ -175,8 +176,8 @@ void bitboards_init() { for (int f = FILE_A; f <= FILE_H; f++) { - NeighboringFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); - ThisAndNeighboringFilesBB[f] = FileBB[f] | NeighboringFilesBB[f]; + AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); + ThisAndAdjacentFilesBB[f] = FileBB[f] | AdjacentFilesBB[f]; } for (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++) @@ -189,8 +190,8 @@ void bitboards_init() { for (Square s = SQ_A1; s <= SQ_H8; s++) { SquaresInFrontMask[c][s] = in_front_bb(c, s) & file_bb(s); - PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_neighboring_files_bb(file_of(s)); - AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(file_of(s)); + PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(file_of(s)); + AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(file_of(s)); } for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) @@ -203,7 +204,7 @@ void bitboards_init() { Bitboard b = 1ULL << i; b ^= b - 1; b ^= b >> 32; - BSFTable[uint32_t(b * 0x783A9B23) >> 26] = i; + BSFTable[(uint32_t)(b * 0x783A9B23) >> 26] = i; } else BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i; @@ -218,56 +219,53 @@ void bitboards_init() { { Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]); - if (square_is_ok(to) && square_distance(s, to) < 3) - set_bit(&StepAttacksBB[make_piece(c, pt)][s], to); + if (is_ok(to) && square_distance(s, to) < 3) + StepAttacksBB[make_piece(c, pt)][s] |= to; } - init_magic_bitboards(ROOK, RAttacks, RMagics, RMasks, RShifts); - init_magic_bitboards(BISHOP, BAttacks, BMagics, BMasks, BShifts); + Square RDeltas[] = { DELTA_N, DELTA_E, DELTA_S, DELTA_W }; + Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW }; + + 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++) { - BishopPseudoAttacks[s] = bishop_attacks_bb(s, 0); - RookPseudoAttacks[s] = rook_attacks_bb(s, 0); - QueenPseudoAttacks[s] = queen_attacks_bb(s, 0); + PseudoAttacks[BISHOP][s] = attacks_bb(s, 0); + PseudoAttacks[ROOK][s] = attacks_bb(s, 0); + PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] | PseudoAttacks[ROOK][s]; } for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) - if (bit_is_set(QueenPseudoAttacks[s1], s2)) + if (PseudoAttacks[QUEEN][s1] & s2) { Square delta = (s2 - s1) / square_distance(s1, s2); for (Square s = s1 + delta; s != s2; s += delta) - set_bit(&BetweenBB[s1][s2], s); + BetweenBB[s1][s2] |= s; } } namespace { - Bitboard sliding_attacks(PieceType pt, Square sq, Bitboard occupied) { + Bitboard sliding_attack(Square deltas[], Square sq, Bitboard occupied) { - Square deltas[][4] = { { DELTA_N, DELTA_E, DELTA_S, DELTA_W }, - { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW } }; - Bitboard attacks = 0; - Square* delta = (pt == ROOK ? deltas[0] : deltas[1]); + Bitboard attack = 0; for (int i = 0; i < 4; i++) - { - Square s = sq + delta[i]; - - while (square_is_ok(s) && square_distance(s, s - delta[i]) == 1) + for (Square s = sq + deltas[i]; + is_ok(s) && square_distance(s, s - deltas[i]) == 1; + s += deltas[i]) { - set_bit(&attacks, s); + attack |= s; - if (bit_is_set(occupied, s)) + if (occupied & s) break; - - s += delta[i]; } - } - return attacks; + + return attack; } @@ -293,22 +291,22 @@ namespace { } - // init_magic_bitboards() computes all rook and bishop magics at startup. - // Magic bitboards are used to look up attacks of sliding pieces. As reference - // see chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we + // init_magics() computes all rook and bishop attacks at startup. Magic + // bitboards are used to look up attacks of sliding pieces. As a reference see + // chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we // use the so called "fancy" approach. - void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[], - Bitboard masks[], int shifts[]) { + void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[], + Bitboard masks[], unsigned shifts[], Square deltas[], Fn index) { int MagicBoosters[][8] = { { 3191, 2184, 1310, 3618, 2091, 1308, 2452, 3996 }, { 1059, 3608, 605, 3234, 3326, 38, 2029, 3043 } }; RKISS rk; Bitboard occupancy[4096], reference[4096], edges, b; - int i, size, index, booster; + int i, size, booster; // attacks[s] is a pointer to the beginning of the attacks table for square 's' - attacks[SQ_A1] = (pt == ROOK ? RookTable : BishopTable); + attacks[SQ_A1] = table; for (Square s = SQ_A1; s <= SQ_H8; s++) { @@ -320,15 +318,15 @@ namespace { // all the attacks for each possible subset of the mask and so is 2 power // the number of 1s of the mask. Hence we deduce the size of the shift to // apply to the 64 or 32 bits word to get the index. - masks[s] = sliding_attacks(pt, s, 0) & ~edges; + masks[s] = sliding_attack(deltas, s, 0) & ~edges; shifts[s] = (Is64Bit ? 64 : 32) - popcount(masks[s]); // Use Carry-Rippler trick to enumerate all subsets of masks[s] and - // store the corresponding sliding attacks bitboard in reference[]. + // store the corresponding sliding attack bitboard in reference[]. b = size = 0; do { occupancy[size] = b; - reference[size++] = sliding_attacks(pt, s, b); + reference[size++] = sliding_attack(deltas, s, b); b = (b - masks[s]) & masks[s]; } while (b); @@ -351,14 +349,12 @@ namespace { // effect of verifying the magic. for (i = 0; i < size; i++) { - index = (pt == ROOK ? rook_index(s, occupancy[i]) - : bishop_index(s, occupancy[i])); - - if (!attacks[s][index]) - attacks[s][index] = reference[i]; + Bitboard& attack = attacks[s][index(s, occupancy[i])]; - else if (attacks[s][index] != reference[i]) + if (attack && attack != reference[i]) break; + + attack = reference[i]; } } while (i != size); }