X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitboard.h;h=390966e3494273969bdb53a50c6953a6c9782611;hb=HEAD;hp=eec8342fb61b0e8ebe7443db0238022d1f5140fb;hpb=17d41b386117f3b93daeb3a183f7a12e46812cdb;p=stockfish
diff --git a/src/bitboard.h b/src/bitboard.h
index eec8342f..7dbd5329 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -1,14 +1,12 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
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
@@ -18,305 +16,359 @@
along with this program. If not, see .
*/
-#if !defined(BITBOARD_H_INCLUDED)
+#ifndef BITBOARD_H_INCLUDED
#define BITBOARD_H_INCLUDED
+#include
+#include
+#include
+#include
+#include
+#include
+
#include "types.h"
+namespace Stockfish {
+
namespace Bitboards {
-void init();
-void print(Bitboard b);
+void init();
+std::string pretty(Bitboard b);
-}
+} // namespace Stockfish::Bitboards
-namespace Bitbases {
+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;
-void init_kpk();
-bool probe_kpk(Square wksq, Square wpsq, Square bksq, Color us);
+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);
-}
+extern uint8_t PopCnt16[1 << 16];
+extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB];
-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);
-
-CACHE_LINE_ALIGNMENT
-
-extern Bitboard RMasks[SQUARE_NB];
-extern Bitboard RMagics[SQUARE_NB];
-extern Bitboard* RAttacks[SQUARE_NB];
-extern unsigned RShifts[SQUARE_NB];
-
-extern Bitboard BMasks[SQUARE_NB];
-extern Bitboard BMagics[SQUARE_NB];
-extern Bitboard* BAttacks[SQUARE_NB];
-extern unsigned BShifts[SQUARE_NB];
-
-extern Bitboard SquareBB[SQUARE_NB];
-extern Bitboard FileBB[FILE_NB];
-extern Bitboard RankBB[RANK_NB];
-extern Bitboard AdjacentFilesBB[FILE_NB];
-extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
-extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
-extern Bitboard DistanceRingsBB[SQUARE_NB][8];
-extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
-extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
-extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
+extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB];
-extern int SquareDistance[SQUARE_NB][SQUARE_NB];
-const Bitboard BlackSquares = 0xAA55AA55AA55AA55ULL;
+// Magic holds all magic bitboards relevant data for a single square
+struct Magic {
+ Bitboard mask;
+ Bitboard magic;
+ Bitboard* attacks;
+ unsigned shift;
-/// 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.
+ // Compute the attack's index using the 'magic bitboards' approach
+ unsigned index(Bitboard occupied) const {
-inline Bitboard operator&(Bitboard b, Square s) {
- return b & SquareBB[s];
-}
+ if (HasPext)
+ return unsigned(pext(occupied, mask));
-inline Bitboard& operator|=(Bitboard& b, Square s) {
- return b |= SquareBB[s];
-}
+ if (Is64Bit)
+ return unsigned(((occupied & mask) * magic) >> shift);
-inline Bitboard& operator^=(Bitboard& b, Square s) {
- return b ^= SquareBB[s];
-}
+ unsigned lo = unsigned(occupied) & unsigned(mask);
+ unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
+ return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
+ }
+};
-inline Bitboard operator|(Bitboard b, Square s) {
- return b | SquareBB[s];
-}
+extern Magic RookMagics[SQUARE_NB];
+extern Magic BishopMagics[SQUARE_NB];
-inline Bitboard operator^(Bitboard b, Square s) {
- return b ^ SquareBB[s];
+inline Bitboard square_bb(Square s) {
+ assert(is_ok(s));
+ return (1ULL << s);
}
-inline bool more_than_one(Bitboard b) {
- return b & (b - 1);
-}
-inline int square_distance(Square s1, Square s2) {
- return SquareDistance[s1][s2];
-}
+// 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.
-inline int file_distance(Square s1, Square s2) {
- return abs(file_of(s1) - file_of(s2));
-}
+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 int rank_distance(Square s1, Square s2) {
- return abs(rank_of(s1) - rank_of(s2));
-}
+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 s1, Square s2) { return square_bb(s1) | s2; }
-/// shift_bb() moves bitboard one step along direction Delta. Mainly for pawns.
+constexpr bool more_than_one(Bitboard b) { return b & (b - 1); }
-template
-inline Bitboard shift_bb(Bitboard b) {
- return Delta == DELTA_N ? b << 8 : Delta == DELTA_S ? b >> 8
- : Delta == DELTA_NE ? (b & ~FileHBB) << 9 : Delta == DELTA_SE ? (b & ~FileHBB) >> 7
- : Delta == DELTA_NW ? (b & ~FileABB) << 7 : Delta == DELTA_SW ? (b & ~FileABB) >> 9
- : 0;
-}
+// rank_bb() and file_bb() return a bitboard representing all the squares on
+// the given file or rank.
+constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); }
-/// 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.
+constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); }
-inline Bitboard rank_bb(Rank r) {
- return RankBB[r];
-}
+constexpr Bitboard file_bb(File f) { return FileABB << f; }
-inline Bitboard rank_bb(Square s) {
- return RankBB[rank_of(s)];
+constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); }
+
+
+// Moves a bitboard one or two steps as specified by the direction D
+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 file_bb(File f) {
- return FileBB[f];
+
+// 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);
}
-inline Bitboard file_bb(Square s) {
- return FileBB[file_of(s)];
+inline Bitboard pawn_attacks_bb(Color c, Square s) {
+
+ assert(is_ok(s));
+ return PawnAttacks[c][s];
}
+// Returns a bitboard representing an entire line (from board edge
+// to board edge) that intersects the two given squares. If the given squares
+// are not on a same file/rank/diagonal, the function returns 0. For instance,
+// line_bb(SQ_C4, SQ_F7) will return a bitboard with the A2-G8 diagonal.
+inline Bitboard line_bb(Square s1, Square s2) {
-/// adjacent_files_bb() takes a file as input and returns a bitboard representing
-/// all squares on the adjacent files.
+ assert(is_ok(s1) && is_ok(s2));
-inline Bitboard adjacent_files_bb(File f) {
- return AdjacentFilesBB[f];
+ return LineBB[s1][s2];
}
-/// in_front_bb() takes a color and a rank as input, and returns a bitboard
-/// representing all the squares on all ranks in front of the rank, from the
-/// given color's point of view. For instance, in_front_bb(BLACK, RANK_3) will
-/// give all squares on ranks 1 and 2.
+// Returns a bitboard representing the squares in the semi-open
+// segment between the squares s1 and s2 (excluding s1 but including s2). If the
+// given squares are not on a same file/rank/diagonal, it returns s2. For instance,
+// between_bb(SQ_C4, SQ_F7) will return a bitboard with squares D5, E6 and F7, but
+// between_bb(SQ_E6, SQ_F8) will return a bitboard with the square F8. This trick
+// allows to generate non-king evasion moves faster: the defending piece must either
+// interpose itself to cover the check or capture the checking piece.
+inline Bitboard between_bb(Square s1, Square s2) {
+
+ assert(is_ok(s1) && is_ok(s2));
-inline Bitboard in_front_bb(Color c, Rank r) {
- return InFrontBB[c][r];
+ return BetweenBB[s1][s2];
}
+// 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 line_bb(s1, s2) & s3; }
-/// between_bb() returns a bitboard representing all squares between two squares.
-/// For instance, between_bb(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,
-/// 0 is returned.
-inline Bitboard between_bb(Square s1, Square s2) {
- return BetweenBB[s1][s2];
-}
+// 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));
+}
-/// forward_bb() 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:
-/// ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s)
+template<>
+inline int distance(Square x, Square y) {
+ return std::abs(rank_of(x) - rank_of(y));
+}
-inline Bitboard forward_bb(Color c, Square s) {
- return ForwardBB[c][s];
+template<>
+inline int distance(Square x, Square y) {
+ return SquareDistance[x][y];
}
+inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); }
+
+// Returns the pseudo attacks of the given piece type
+// assuming an empty board.
+template
+inline Bitboard attacks_bb(Square s) {
-/// pawn_attack_span() 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:
-/// PawnAttackSpan[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
+ assert((Pt != PAWN) && (is_ok(s)));
-inline Bitboard pawn_attack_span(Color c, Square s) {
- return PawnAttackSpan[c][s];
+ 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] = pawn_attack_span(c, s) | forward_bb(c, s)
+// Returns the attacks by the given piece
+// assuming the board is occupied according to the passed Bitboard.
+// Sliding piece attacks do not continue passed an occupied square.
+template
+inline Bitboard attacks_bb(Square s, Bitboard occupied) {
+
+ assert((Pt != PAWN) && (is_ok(s)));
-inline Bitboard passed_pawn_mask(Color c, Square s) {
- return PassedPawnMask[c][s];
+ switch (Pt)
+ {
+ case BISHOP :
+ return BishopMagics[s].attacks[BishopMagics[s].index(occupied)];
+ case ROOK :
+ return RookMagics[s].attacks[RookMagics[s].index(occupied)];
+ case QUEEN :
+ return attacks_bb(s, occupied) | attacks_bb(s, occupied);
+ default :
+ return PseudoAttacks[Pt][s];
+ }
}
+// Returns the attacks by the given piece
+// assuming the board is occupied according to the passed Bitboard.
+// Sliding piece attacks do not continue passed an occupied square.
+inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
-/// squares_aligned() returns true if the squares s1, s2 and s3 are aligned
-/// either on a straight or on a diagonal line.
+ assert((pt != PAWN) && (is_ok(s)));
-inline bool squares_aligned(Square s1, Square s2, Square s3) {
- return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
- & ( SquareBB[s1] | SquareBB[s2] | SquareBB[s3]);
+ switch (pt)
+ {
+ case BISHOP :
+ return attacks_bb(s, occupied);
+ case ROOK :
+ return attacks_bb(s, occupied);
+ case QUEEN :
+ return attacks_bb(s, occupied) | attacks_bb(s, occupied);
+ default :
+ return PseudoAttacks[pt][s];
+ }
}
-/// same_color_squares() returns a bitboard representing all squares with
-/// the same color of the given square.
+// Counts the number of non-zero bits in a bitboard.
+inline int popcount(Bitboard b) {
-inline Bitboard same_color_squares(Square s) {
- return BlackSquares & s ? BlackSquares : ~BlackSquares;
-}
+#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]];
-/// Functions for computing sliding attack bitboards. Function attacks_bb() takes
-/// a square and a bitboard of occupied squares as input, and returns a bitboard
-/// representing all squares attacked by Pt (bishop or rook) on the given square.
-template
-FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
+#elif defined(_MSC_VER)
- Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks;
- Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
- unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
+ return int(_mm_popcnt_u64(b));
- if (Is64Bit)
- return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
+#else // Assumed gcc or compatible compiler
- unsigned lo = unsigned(occ) & unsigned(Masks[s]);
- unsigned hi = unsigned(occ >> 32) & unsigned(Masks[s] >> 32);
- return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
-}
+ return __builtin_popcountll(b);
-template
-inline Bitboard attacks_bb(Square s, Bitboard occ) {
- return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index(s, occ)];
+#endif
}
+// Returns the least significant bit in a non-zero bitboard.
+inline Square lsb(Bitboard b) {
+ assert(b);
-/// 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)
+#if defined(__GNUC__) // GCC, Clang, ICX
-# if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
+ return Square(__builtin_ctzll(b));
-FORCE_INLINE Square lsb(Bitboard b) {
- unsigned long index;
- _BitScanForward64(&index, b);
- return (Square) index;
-}
+#elif defined(_MSC_VER)
+ #ifdef _WIN64 // MSVC, WIN64
-FORCE_INLINE Square msb(Bitboard b) {
- unsigned long index;
- _BitScanReverse64(&index, b);
- return (Square) index;
-}
+ unsigned long idx;
+ _BitScanForward64(&idx, b);
+ return Square(idx);
-# elif defined(__arm__)
+ #else // MSVC, WIN32
+ unsigned long idx;
-FORCE_INLINE int lsb32(uint32_t v) {
- __asm__("rbit %0, %1" : "=r"(v) : "r"(v));
- return __builtin_clz(v);
+ if (b & 0xffffffff)
+ {
+ _BitScanForward(&idx, int32_t(b));
+ return Square(idx);
+ }
+ else
+ {
+ _BitScanForward(&idx, int32_t(b >> 32));
+ return Square(idx + 32);
+ }
+ #endif
+#else // Compiler is neither GCC nor MSVC compatible
+ #error "Compiler not supported."
+#endif
}
-FORCE_INLINE Square msb(Bitboard b) {
- return (Square) (63 - __builtin_clzll(b));
-}
+// Returns the most significant bit in a non-zero bitboard.
+inline Square msb(Bitboard b) {
+ assert(b);
-FORCE_INLINE Square lsb(Bitboard b) {
- return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32)));
-}
+#if defined(__GNUC__) // GCC, Clang, ICX
-# else
+ return Square(63 ^ __builtin_clzll(b));
-FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen
- Bitboard index;
- __asm__("bsfq %1, %0": "=r"(index): "rm"(b) );
- return (Square) index;
-}
+#elif defined(_MSC_VER)
+ #ifdef _WIN64 // MSVC, WIN64
-FORCE_INLINE Square msb(Bitboard b) {
- Bitboard index;
- __asm__("bsrq %1, %0": "=r"(index): "rm"(b) );
- return (Square) index;
-}
+ unsigned long idx;
+ _BitScanReverse64(&idx, b);
+ return Square(idx);
+
+ #else // MSVC, WIN32
-# endif
+ unsigned long idx;
-FORCE_INLINE Square pop_lsb(Bitboard* b) {
- const Square s = lsb(*b);
- *b &= *b - 1;
- return s;
+ if (b >> 32)
+ {
+ _BitScanReverse(&idx, int32_t(b >> 32));
+ return Square(idx + 32);
+ }
+ else
+ {
+ _BitScanReverse(&idx, int32_t(b));
+ return Square(idx);
+ }
+ #endif
+#else // Compiler is neither GCC nor MSVC compatible
+ #error "Compiler not supported."
+#endif
}
-#else // if !defined(USE_BSFQ)
+// Returns the bitboard of the least significant
+// square of a non-zero bitboard. It is equivalent to square_bb(lsb(bb)).
+inline Bitboard least_significant_square_bb(Bitboard b) {
+ assert(b);
+ return b & -b;
+}
-extern Square msb(Bitboard b);
-extern Square lsb(Bitboard b);
-extern Square pop_lsb(Bitboard* b);
+// Finds and clears the least significant bit in a non-zero bitboard.
+inline Square pop_lsb(Bitboard& b) {
+ assert(b);
+ const Square s = lsb(b);
+ b &= b - 1;
+ return s;
+}
-#endif
+} // namespace Stockfish
-#endif // !defined(BITBOARD_H_INCLUDED)
+#endif // #ifndef BITBOARD_H_INCLUDED