X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=8d748eeed8615628ddd4b044df9c34aef4fcaeff;hp=b962226bfb9e5048f950a2dd954622e48db28f7d;hb=3ef0c3c34a00e6b13d6c96d8c2f0d8d7a6cc25a6;hpb=0fcda095df1caa860e8e3f3a714d5545ec9dc122
diff --git a/src/bitboard.h b/src/bitboard.h
index b962226b..8d748eee 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -1,14 +1,14 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2019 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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
@@ -18,268 +18,373 @@
along with this program. If not, see .
*/
-#if !defined(BITBOARD_H_INCLUDED)
+#ifndef BITBOARD_H_INCLUDED
#define BITBOARD_H_INCLUDED
+#include
+
#include "types.h"
-const Bitboard EmptyBoardBB = 0;
-
-const Bitboard FileABB = 0x0101010101010101ULL;
-const Bitboard FileBBB = FileABB << 1;
-const Bitboard FileCBB = FileABB << 2;
-const Bitboard FileDBB = FileABB << 3;
-const Bitboard FileEBB = FileABB << 4;
-const Bitboard FileFBB = FileABB << 5;
-const Bitboard FileGBB = FileABB << 6;
-const Bitboard FileHBB = FileABB << 7;
-
-const Bitboard Rank1BB = 0xFF;
-const Bitboard Rank2BB = Rank1BB << (8 * 1);
-const Bitboard Rank3BB = Rank1BB << (8 * 2);
-const Bitboard Rank4BB = Rank1BB << (8 * 3);
-const Bitboard Rank5BB = Rank1BB << (8 * 4);
-const Bitboard Rank6BB = Rank1BB << (8 * 5);
-const Bitboard Rank7BB = Rank1BB << (8 * 6);
-const Bitboard Rank8BB = Rank1BB << (8 * 7);
-
-extern const Bitboard SquaresByColorBB[2];
-extern const Bitboard FileBB[8];
-extern const Bitboard NeighboringFilesBB[8];
-extern const Bitboard ThisAndNeighboringFilesBB[8];
-extern const Bitboard RankBB[8];
-extern const Bitboard InFrontBB[2][8];
-
-extern Bitboard SetMaskBB[65];
-extern Bitboard ClearMaskBB[65];
-
-extern Bitboard NonSlidingAttacksBB[16][64];
-extern Bitboard BetweenBB[64][64];
-
-extern Bitboard SquaresInFrontMask[2][64];
-extern Bitboard PassedPawnMask[2][64];
-extern Bitboard AttackSpanMask[2][64];
-
-extern const uint64_t RMult[64];
-extern const int RShift[64];
-extern Bitboard RMask[64];
-extern int RAttackIndex[64];
-extern Bitboard RAttacks[0x19000];
-
-extern const uint64_t BMult[64];
-extern const int BShift[64];
-extern Bitboard BMask[64];
-extern int BAttackIndex[64];
-extern Bitboard BAttacks[0x1480];
-
-extern Bitboard BishopPseudoAttacks[64];
-extern Bitboard RookPseudoAttacks[64];
-extern Bitboard QueenPseudoAttacks[64];
-
-extern uint8_t BitCount8Bit[256];
-
-
-/// Functions for testing whether a given bit is set in a bitboard, and for
-/// setting and clearing bits.
-
-inline Bitboard bit_is_set(Bitboard b, Square s) {
- return b & SetMaskBB[s];
+namespace Bitbases {
+
+void init();
+bool probe(Square wksq, Square wpsq, Square bksq, Color us);
+
}
-inline void set_bit(Bitboard *b, Square s) {
- *b |= SetMaskBB[s];
+namespace Bitboards {
+
+void init();
+const std::string pretty(Bitboard b);
+
}
-inline void clear_bit(Bitboard *b, Square s) {
- *b &= ClearMaskBB[s];
+constexpr Bitboard AllSquares = ~Bitboard(0);
+constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
+
+constexpr Bitboard FileABB = 0x0101010101010101ULL;
+constexpr Bitboard FileBBB = FileABB << 1;
+constexpr Bitboard FileCBB = FileABB << 2;
+constexpr Bitboard FileDBB = FileABB << 3;
+constexpr Bitboard FileEBB = FileABB << 4;
+constexpr Bitboard FileFBB = FileABB << 5;
+constexpr Bitboard FileGBB = FileABB << 6;
+constexpr Bitboard FileHBB = FileABB << 7;
+
+constexpr Bitboard Rank1BB = 0xFF;
+constexpr Bitboard Rank2BB = Rank1BB << (8 * 1);
+constexpr Bitboard Rank3BB = Rank1BB << (8 * 2);
+constexpr Bitboard Rank4BB = Rank1BB << (8 * 3);
+constexpr Bitboard Rank5BB = Rank1BB << (8 * 4);
+constexpr Bitboard Rank6BB = Rank1BB << (8 * 5);
+constexpr Bitboard Rank7BB = Rank1BB << (8 * 6);
+constexpr Bitboard Rank8BB = Rank1BB << (8 * 7);
+
+constexpr Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
+constexpr Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+constexpr Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
+constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
+
+constexpr Bitboard KingFlank[FILE_NB] = {
+ QueenSide ^ FileDBB, QueenSide, QueenSide,
+ CenterFiles, CenterFiles,
+ KingSide, KingSide, KingSide ^ FileEBB
+};
+
+extern uint8_t PopCnt16[1 << 16];
+extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB];
+
+extern Bitboard SquareBB[SQUARE_NB];
+extern Bitboard LineBB[SQUARE_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];
+
+inline Bitboard square_bb(Square s) {
+ assert(s >= SQ_A1 && s <= SQ_H8);
+ return SquareBB[s];
}
+/// Overloads of bitwise operators between a Bitboard and a Square for testing
+/// whether a given bit is set in a bitboard, and for setting and clearing bits.
-/// Functions used to update a bitboard after a move. This is faster
-/// then calling a sequence of clear_bit() + set_bit()
+inline Bitboard operator&( Bitboard b, Square s) { return b & square_bb(s); }
+inline Bitboard operator|( Bitboard b, Square s) { return b | square_bb(s); }
+inline Bitboard operator^( Bitboard b, Square s) { return b ^ square_bb(s); }
+inline Bitboard& operator|=(Bitboard& b, Square s) { return b |= square_bb(s); }
+inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= square_bb(s); }
-inline Bitboard make_move_bb(Square from, Square to) {
- return SetMaskBB[from] | SetMaskBB[to];
+inline Bitboard operator&(Square s, Bitboard b) { return b & s; }
+inline Bitboard operator|(Square s, Bitboard b) { return b | s; }
+inline Bitboard operator^(Square s, Bitboard b) { return b ^ s; }
+
+inline Bitboard operator|(Square s, Square s2) { return square_bb(s) | square_bb(s2); }
+
+constexpr bool more_than_one(Bitboard b) {
+ return b & (b - 1);
}
-inline void do_move_bb(Bitboard *b, Bitboard move_bb) {
- *b ^= move_bb;
+inline bool opposite_colors(Square s1, Square s2) {
+ return bool(DarkSquares & s1) != bool(DarkSquares & s2);
}
-/// rank_bb() and file_bb() take a file or a square as input and return
-/// a bitboard representing all squares on the given file or rank.
+/// rank_bb() and file_bb() return a bitboard representing all the squares on
+/// the given file or rank.
inline Bitboard rank_bb(Rank r) {
- return RankBB[r];
+ return Rank1BB << (8 * r);
}
inline Bitboard rank_bb(Square s) {
- return RankBB[square_rank(s)];
+ return rank_bb(rank_of(s));
}
inline Bitboard file_bb(File f) {
- return FileBB[f];
+ return FileABB << f;
}
inline Bitboard file_bb(Square s) {
- return FileBB[square_file(s)];
+ return file_bb(file_of(s));
}
-/// neighboring_files_bb takes a file or a square as input and returns a
-/// bitboard representing all squares on the neighboring files.
+/// shift() moves a bitboard one step along direction D
-inline Bitboard neighboring_files_bb(File f) {
- return NeighboringFilesBB[f];
+template
+constexpr Bitboard shift(Bitboard b) {
+ return D == NORTH ? b << 8 : D == SOUTH ? b >> 8
+ : D == NORTH+NORTH? b <<16 : D == SOUTH+SOUTH? b >>16
+ : D == EAST ? (b & ~FileHBB) << 1 : D == WEST ? (b & ~FileABB) >> 1
+ : D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == NORTH_WEST ? (b & ~FileABB) << 7
+ : D == SOUTH_EAST ? (b & ~FileHBB) >> 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9
+ : 0;
}
-inline Bitboard neighboring_files_bb(Square s) {
- return NeighboringFilesBB[square_file(s)];
+
+/// pawn_attacks_bb() returns the squares attacked by pawns of the given color
+/// from the squares in the given bitboard.
+
+template
+constexpr Bitboard pawn_attacks_bb(Bitboard b) {
+ return C == WHITE ? shift(b) | shift(b)
+ : shift(b) | shift(b);
}
-/// this_and_neighboring_files_bb takes a file or a square as input and returns
-/// a bitboard representing all squares on the given and neighboring files.
+/// pawn_double_attacks_bb() returns the squares doubly attacked by pawns of the
+/// given color from the squares in the given bitboard.
-inline Bitboard this_and_neighboring_files_bb(File f) {
- return ThisAndNeighboringFilesBB[f];
+template
+constexpr Bitboard pawn_double_attacks_bb(Bitboard b) {
+ return C == WHITE ? shift(b) & shift(b)
+ : shift(b) & shift(b);
}
-inline Bitboard this_and_neighboring_files_bb(Square s) {
- return ThisAndNeighboringFilesBB[square_file(s)];
+
+/// adjacent_files_bb() returns a bitboard representing all the squares on the
+/// adjacent files of the given one.
+
+inline Bitboard adjacent_files_bb(Square s) {
+ return shift(file_bb(s)) | shift(file_bb(s));
}
-/// in_front_bb() takes a color and a rank or square as input, and returns a
-/// bitboard representing all the squares on all ranks in front of the rank
-/// (or square), from the given color's point of view. For instance,
-/// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
-/// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
+/// between_bb() returns squares that are linearly between the given squares
+/// If the given squares are not on a same file/rank/diagonal, return 0.
-inline Bitboard in_front_bb(Color c, Rank r) {
- return InFrontBB[c][r];
+inline Bitboard between_bb(Square s1, Square s2) {
+ return LineBB[s1][s2] & ( (AllSquares << (s1 + (s1 < s2)))
+ ^(AllSquares << (s2 + !(s1 < s2))));
}
-inline Bitboard in_front_bb(Color c, Square s) {
- return InFrontBB[c][square_rank(s)];
-}
+/// forward_ranks_bb() returns a bitboard representing the squares on the ranks
+/// in front of the given one, from the point of view of the given color. For instance,
+/// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2.
+
+inline Bitboard forward_ranks_bb(Color c, Square s) {
+ return c == WHITE ? ~Rank1BB << 8 * (rank_of(s) - RANK_1)
+ : ~Rank8BB >> 8 * (RANK_8 - rank_of(s));
+}
-/// Functions for computing sliding attack bitboards. rook_attacks_bb(),
-/// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
-/// bitboard of occupied squares as input, and return a bitboard representing
-/// all squares attacked by a rook, bishop or queen on the given square.
-#if defined(IS_64BIT)
+/// 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.
-inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
- Bitboard b = blockers & RMask[s];
- return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
+inline Bitboard forward_file_bb(Color c, Square s) {
+ return forward_ranks_bb(c, s) & file_bb(s);
}
-inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
- Bitboard b = blockers & BMask[s];
- return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[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.
+
+inline Bitboard pawn_attack_span(Color c, Square s) {
+ return forward_ranks_bb(c, s) & adjacent_files_bb(s);
}
-#else // if !defined(IS_64BIT)
-inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
- Bitboard b = blockers & RMask[s];
- return RAttacks[RAttackIndex[s] +
- (unsigned(int(b) * int(RMult[s]) ^ int(b >> 32) * int(RMult[s] >> 32)) >> RShift[s])];
+/// passed_pawn_span() returns a bitboard which can be used to test if a pawn of
+/// the given color and on the given square is a passed pawn.
+
+inline Bitboard passed_pawn_span(Color c, Square s) {
+ return forward_ranks_bb(c, s) & (adjacent_files_bb(s) | file_bb(s));
}
-inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
- Bitboard b = blockers & BMask[s];
- return BAttacks[BAttackIndex[s] +
- (unsigned(int(b) * int(BMult[s]) ^ int(b >> 32) * int(BMult[s] >> 32)) >> BShift[s])];
+
+/// aligned() returns true if the squares s1, s2 and s3 are aligned either on a
+/// straight or on a diagonal line.
+
+inline bool aligned(Square s1, Square s2, Square s3) {
+ return LineBB[s1][s2] & s3;
}
-#endif
-inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
- return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
+/// distance() functions return the distance between x and y, defined as the
+/// number of steps for a king in x to reach y.
+
+template inline int distance(Square x, Square y);
+template<> inline int distance(Square x, Square y) { return std::abs(file_of(x) - file_of(y)); }
+template<> inline int distance(Square x, Square y) { return std::abs(rank_of(x) - rank_of(y)); }
+template<> inline int distance(Square x, Square y) { return SquareDistance[x][y]; }
+
+template constexpr const T& clamp(const T& v, const T& lo, const T& hi) {
+ return v < lo ? lo : v > hi ? hi : v;
}
+/// attacks_bb() returns a bitboard representing all the squares attacked by a
+/// piece of type Pt (bishop or rook) placed on 's'.
-/// squares_between returns a bitboard representing all squares between
-/// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
-/// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
-/// on the same line, file or diagonal, EmptyBoardBB is returned.
+template
+inline Bitboard attacks_bb(Square s, Bitboard occupied) {
-inline Bitboard squares_between(Square s1, Square s2) {
- return BetweenBB[s1][s2];
+ const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
+ return m.attacks[m.index(occupied)];
}
+inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
-/// squares_in_front_of takes a color and a square as input, and returns a
-/// bitboard representing all squares along the line in front of the square,
-/// from the point of view of the given color. Definition of the table is:
-/// SquaresInFrontOf[c][s] = in_front_bb(c, s) & file_bb(s)
+ assert(pt != PAWN);
-inline Bitboard squares_in_front_of(Color c, Square s) {
- return SquaresInFrontMask[c][s];
+ switch (pt)
+ {
+ case BISHOP: 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 PseudoAttacks[pt][s];
+ }
}
-/// passed_pawn_mask takes a color and a square as input, and returns a
-/// bitboard mask which can be used to test if a pawn of the given color on
-/// the given square is a passed pawn. Definition of the table is:
-/// PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_neighboring_files_bb(s)
+/// popcount() counts the number of non-zero bits in a bitboard
+
+inline int popcount(Bitboard b) {
+
+#ifndef USE_POPCNT
+
+ 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);
-inline Bitboard passed_pawn_mask(Color c, Square s) {
- return PassedPawnMask[c][s];
+#else // Assumed gcc or compatible compiler
+
+ return __builtin_popcountll(b);
+
+#endif
}
-/// attack_span_mask takes a color and a square as input, and returns a bitboard
-/// representing all squares that can be attacked by a pawn of the given color
-/// when it moves along its file starting from the given square. Definition is:
-/// AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
+/// lsb() and msb() return the least/most significant bit in a non-zero bitboard
+
+#if defined(__GNUC__) // GCC, Clang, ICC
+
+inline Square lsb(Bitboard b) {
+ assert(b);
+ return Square(__builtin_ctzll(b));
+}
-inline Bitboard attack_span_mask(Color c, Square s) {
- return AttackSpanMask[c][s];
+inline Square msb(Bitboard b) {
+ assert(b);
+ return Square(63 ^ __builtin_clzll(b));
}
+#elif defined(_MSC_VER) // MSVC
-/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
-/// either on a straight or on a diagonal line.
+#ifdef _WIN64 // MSVC, WIN64
-inline bool squares_aligned(Square s1, Square s2, Square s3) {
- return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
- & ((1ULL << s1) | (1ULL << s2) | (1ULL << s3));
+inline Square lsb(Bitboard b) {
+ assert(b);
+ unsigned long idx;
+ _BitScanForward64(&idx, b);
+ return (Square) idx;
}
+inline Square msb(Bitboard b) {
+ assert(b);
+ unsigned long idx;
+ _BitScanReverse64(&idx, b);
+ return (Square) idx;
+}
-/// 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.
+#else // MSVC, WIN32
-#if defined(USE_BSFQ) // Assembly code by Heinz van Saanen
+inline Square lsb(Bitboard b) {
+ assert(b);
+ unsigned long idx;
-inline Square first_1(Bitboard b) {
- Bitboard dummy;
- __asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
- return (Square)(dummy);
+ if (b & 0xffffffff) {
+ _BitScanForward(&idx, int32_t(b));
+ return Square(idx);
+ } else {
+ _BitScanForward(&idx, int32_t(b >> 32));
+ return Square(idx + 32);
+ }
}
-inline Square pop_1st_bit(Bitboard* b) {
- const Square s = first_1(*b);
- *b &= ~(1ULL<> 32) {
+ _BitScanReverse(&idx, int32_t(b >> 32));
+ return Square(idx + 32);
+ } else {
+ _BitScanReverse(&idx, int32_t(b));
+ return Square(idx);
+ }
}
-#else // if !defined(USE_BSFQ)
+#endif
+
+#else // Compiler is neither GCC nor MSVC compatible
-extern Square first_1(Bitboard b);
-extern Square pop_1st_bit(Bitboard* b);
+#error "Compiler not supported."
#endif
-extern void print_bitboard(Bitboard b);
-extern void init_bitboards();
+/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard
+
+inline Square pop_lsb(Bitboard* b) {
+ const Square s = lsb(*b);
+ *b &= *b - 1;
+ return s;
+}
+
+
+/// frontmost_sq() returns the most advanced square for the given color
+inline Square frontmost_sq(Color c, Bitboard b) {
+ return c == WHITE ? msb(b) : lsb(b);
+}
-#endif // !defined(BITBOARD_H_INCLUDED)
+#endif // #ifndef BITBOARD_H_INCLUDED