X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=8be7cea4b6ae6b098dfa2537904d0885ed2daa8f;hp=ebd048be8474800eb6507a5dfb64bfacc18061eb;hb=0446fc85dec483d1887adc22a3d729b0cacd8328;hpb=374c9e6b63d0e233371ae38cc054d885f2117884 diff --git a/src/bitboard.cpp b/src/bitboard.cpp index ebd048be..8be7cea4 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -45,12 +45,11 @@ Bitboard ThisAndAdjacentFilesBB[8]; Bitboard InFrontBB[2][8]; Bitboard StepAttacksBB[16][64]; Bitboard BetweenBB[64][64]; -Bitboard SquaresInFrontMask[2][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]; namespace { @@ -61,6 +60,7 @@ namespace { int MS1BTable[256]; 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); @@ -68,24 +68,6 @@ namespace { Bitboard masks[], unsigned shifts[], Square deltas[], Fn index); } - -/// print_bitboard() prints a bitboard in an easily readable format to the -/// standard output. This is sometimes useful for debugging. - -void print_bitboard(Bitboard b) { - - for (Rank r = RANK_8; r >= RANK_1; r--) - { - std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; - for (File f = FILE_A; f <= FILE_H; f++) - std::cout << "| " << ((b & make_square(f, r)) ? "X " : " "); - - std::cout << "|\n"; - } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; -} - - /// 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. @@ -110,62 +92,72 @@ Square first_1(Bitboard b) { return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } -// Use type-punning -union b_union { - - Bitboard dummy; - struct { -#if defined (BIGENDIAN) - uint32_t h; - uint32_t l; -#else - uint32_t l; - uint32_t h; -#endif - } b; -}; - Square pop_1st_bit(Bitboard* b) { - const b_union u = *((b_union*)b); - - if (u.b.l) - { - ((b_union*)b)->b.l = u.b.l & (u.b.l - 1); - return Square(BSFTable[((u.b.l ^ (u.b.l - 1)) * 0x783A9B23) >> 26]); - } - - ((b_union*)b)->b.h = u.b.h & (u.b.h - 1); - return Square(BSFTable[((~(u.b.h ^ (u.b.h - 1))) * 0x783A9B23) >> 26]); + Bitboard bb = *b; + *b = bb & (bb - 1); + bb ^= (bb - 1); + uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32); + return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } -#endif // !defined(USE_BSFQ) - -#if !defined(USE_BSFQ) - Square last_1(Bitboard b) { + + unsigned b32; int result = 0; - if (b > 0xFFFFFFFF) { - b >>= 32; - result = 32; + + if (b > 0xFFFFFFFF) + { + b >>= 32; + result = 32; } - if (b > 0xFFFF) { - b >>= 16; - result += 16; + + b32 = unsigned(b); + + if (b32 > 0xFFFF) + { + b32 >>= 16; + result += 16; } - if (b > 0xFF) { - b >>= 8; - result += 8; + + if (b32 > 0xFF) + { + b32 >>= 8; + result += 8; } - return Square(result + MS1BTable[b]); + + 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); @@ -176,30 +168,27 @@ void bitboards_init() { FileBB[FILE_A] = FileABB; RankBB[RANK_1] = Rank1BB; - for (int f = FILE_B; f <= FILE_H; f++) + for (int i = 1; i < 8; i++) { - FileBB[f] = FileBB[f - 1] << 1; - RankBB[f] = RankBB[f - 1] << 8; + FileBB[i] = FileBB[i - 1] << 1; + RankBB[i] = RankBB[i - 1] << 8; } - for (int 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 (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++) - { - InFrontBB[WHITE][rw] = InFrontBB[WHITE][rw + 1] | RankBB[rw + 1]; - InFrontBB[BLACK][rb] = InFrontBB[BLACK][rb - 1] | RankBB[rb - 1]; - } + 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++) { - SquaresInFrontMask[c][s] = in_front_bb(c, s) & file_bb(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)); + 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)]; } for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) @@ -217,11 +206,6 @@ void bitboards_init() { else BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i; - MS1BTable[0] = 0; - for (int i = 0, k = 1; i < 8; i++) - for (int j = 0; j < (1 << i); j++) - MS1BTable[k++] = i; - int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 }, {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } }; @@ -232,7 +216,7 @@ 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) + if (is_ok(to) && square_distance(s, to) < 3) StepAttacksBB[make_piece(c, pt)][s] |= to; } @@ -244,9 +228,8 @@ void bitboards_init() { for (Square s = SQ_A1; s <= SQ_H8; s++) { - PseudoAttacks[BISHOP][s] = attacks_bb(s, 0); - PseudoAttacks[ROOK][s] = attacks_bb(s, 0); - PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] | PseudoAttacks[ROOK][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++) @@ -269,7 +252,7 @@ namespace { for (int i = 0; i < 4; i++) for (Square s = sq + deltas[i]; - square_is_ok(s) && square_distance(s, s - deltas[i]) == 1; + is_ok(s) && square_distance(s, s - deltas[i]) == 1; s += deltas[i]) { attack |= s; @@ -282,25 +265,17 @@ 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(); } @@ -353,7 +328,9 @@ 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); + do magics[s] = pick_random(rk, booster); + while (BitCount8Bit[(magics[s] * masks[s]) >> 56] < 6); + memset(attacks[s], 0, size * sizeof(Bitboard)); // A good magic must map every possible occupancy to an index that @@ -367,6 +344,8 @@ namespace { if (attack && attack != reference[i]) break; + assert(reference[i] != 0); + attack = reference[i]; } } while (i != size);