/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-#if !defined(BITBOARD_H_INCLUDED)
+#ifndef BITBOARD_H_INCLUDED
#define BITBOARD_H_INCLUDED
-////
-//// Defines
-////
+#include "types.h"
-// Quiet a warning on Intel compiler
-#if !defined(__SIZEOF_INT__ )
-#define __SIZEOF_INT__ 0
-#endif
+namespace Bitboards {
-// Check for 64 bits for different compilers: Intel, MSVC and gcc
-#if defined(__x86_64) || defined(_WIN64) || (__SIZEOF_INT__ > 4)
-#define IS_64BIT
-#endif
+void init();
+void print(Bitboard b);
-#if defined(IS_64BIT) && (defined(__GNUC__) || defined(__INTEL_COMPILER))
-#define USE_BSFQ
-#endif
+}
+namespace Bitbases {
-////
-//// Includes
-////
+void init_kpk();
+bool probe_kpk(Square wksq, Square wpsq, Square bksq, Color us);
-#include "direction.h"
-#include "piece.h"
-#include "square.h"
-#include "types.h"
+}
+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;
-////
-//// Types
-////
+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);
-typedef uint64_t Bitboard;
+CACHE_LINE_ALIGNMENT
+extern Bitboard RMasks[SQUARE_NB];
+extern Bitboard RMagics[SQUARE_NB];
+extern Bitboard* RAttacks[SQUARE_NB];
+extern unsigned RShifts[SQUARE_NB];
-////
-//// Constants and variables
-////
+extern Bitboard BMasks[SQUARE_NB];
+extern Bitboard BMagics[SQUARE_NB];
+extern Bitboard* BAttacks[SQUARE_NB];
+extern unsigned BShifts[SQUARE_NB];
-const Bitboard EmptyBoardBB = 0ULL;
+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 PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
-const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
-const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
-const Bitboard SquaresByColorBB[2] = { BlackSquaresBB, WhiteSquaresBB };
+extern int SquareDistance[SQUARE_NB][SQUARE_NB];
-const Bitboard FileABB = 0x0101010101010101ULL;
-const Bitboard FileBBB = 0x0202020202020202ULL;
-const Bitboard FileCBB = 0x0404040404040404ULL;
-const Bitboard FileDBB = 0x0808080808080808ULL;
-const Bitboard FileEBB = 0x1010101010101010ULL;
-const Bitboard FileFBB = 0x2020202020202020ULL;
-const Bitboard FileGBB = 0x4040404040404040ULL;
-const Bitboard FileHBB = 0x8080808080808080ULL;
-
-const Bitboard FileBB[8] = {
- FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB
-};
-
-const Bitboard NeighboringFilesBB[8] = {
- FileBBB, FileABB|FileCBB, FileBBB|FileDBB, FileCBB|FileEBB,
- FileDBB|FileFBB, FileEBB|FileGBB, FileFBB|FileHBB, FileGBB
-};
-
-const Bitboard ThisAndNeighboringFilesBB[8] = {
- FileABB|FileBBB, FileABB|FileBBB|FileCBB,
- FileBBB|FileCBB|FileDBB, FileCBB|FileDBB|FileEBB,
- FileDBB|FileEBB|FileFBB, FileEBB|FileFBB|FileGBB,
- FileFBB|FileGBB|FileHBB, FileGBB|FileHBB
-};
-
-const Bitboard Rank1BB = 0xFFULL;
-const Bitboard Rank2BB = 0xFF00ULL;
-const Bitboard Rank3BB = 0xFF0000ULL;
-const Bitboard Rank4BB = 0xFF000000ULL;
-const Bitboard Rank5BB = 0xFF00000000ULL;
-const Bitboard Rank6BB = 0xFF0000000000ULL;
-const Bitboard Rank7BB = 0xFF000000000000ULL;
-const Bitboard Rank8BB = 0xFF00000000000000ULL;
-
-const Bitboard RankBB[8] = {
- Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB
-};
-
-const Bitboard RelativeRankBB[2][8] = {
- { Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB },
- { Rank8BB, Rank7BB, Rank6BB, Rank5BB, Rank4BB, Rank3BB, Rank2BB, Rank1BB }
-};
-
-const Bitboard InFrontBB[2][8] = {
- { Rank2BB | Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
- Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
- Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
- Rank5BB | Rank6BB | Rank7BB | Rank8BB,
- Rank6BB | Rank7BB | Rank8BB,
- Rank7BB | Rank8BB,
- Rank8BB,
- EmptyBoardBB
- },
- { EmptyBoardBB,
- Rank1BB,
- Rank2BB | Rank1BB,
- Rank3BB | Rank2BB | Rank1BB,
- Rank4BB | Rank3BB | Rank2BB | Rank1BB,
- Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
- Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
- Rank7BB | Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB
- }
-};
-
-const int BitTable[64] = {
- 63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2,
- 51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, 52,
- 26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, 28,
- 58, 20, 37, 17, 36, 8
-};
-
-extern Bitboard SetMaskBB[65];
-extern Bitboard ClearMaskBB[65];
-
-extern Bitboard StepAttackBB[16][64];
-extern Bitboard RayBB[64][8];
-extern Bitboard BetweenBB[64][64];
-
-extern Bitboard PassedPawnMask[2][64];
-extern Bitboard OutpostMask[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];
-
-
-////
-//// Inline functions
-////
-
-/// 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];
-}
+const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
-inline void set_bit(Bitboard *b, Square s) {
- *b |= SetMaskBB[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.
-inline void clear_bit(Bitboard *b, Square s) {
- *b &= ClearMaskBB[s];
+inline Bitboard operator&(Bitboard b, Square s) {
+ return b & SquareBB[s];
}
+inline Bitboard& operator|=(Bitboard& b, Square s) {
+ return b |= SquareBB[s];
+}
-/// Functions used to update a bitboard after a move. This is faster
-/// then calling a sequence of clear_bit() + set_bit()
-
-inline Bitboard make_move_bb(Square from, Square to) {
- return SetMaskBB[from] | SetMaskBB[to];
+inline Bitboard& operator^=(Bitboard& b, Square s) {
+ return b ^= SquareBB[s];
}
-inline void do_move_bb(Bitboard *b, Bitboard move_bb) {
- *b ^= move_bb;
+inline Bitboard operator|(Bitboard b, Square s) {
+ return b | SquareBB[s];
}
-/// rank_bb() and file_bb() gives a bitboard containing all squares on a given
-/// file or rank. It is also possible to pass a square as input to these
-/// functions.
+inline Bitboard operator^(Bitboard b, Square s) {
+ return b ^ SquareBB[s];
+}
-inline Bitboard rank_bb(Rank r) {
- return RankBB[r];
+inline bool more_than_one(Bitboard b) {
+ return b & (b - 1);
}
-inline Bitboard rank_bb(Square s) {
- return rank_bb(square_rank(s));
+inline int square_distance(Square s1, Square s2) {
+ return SquareDistance[s1][s2];
}
-inline Bitboard file_bb(File f) {
- return FileBB[f];
+inline int file_distance(Square s1, Square s2) {
+ return abs(file_of(s1) - file_of(s2));
}
-inline Bitboard file_bb(Square s) {
- return file_bb(square_file(s));
+inline int rank_distance(Square s1, Square s2) {
+ return abs(rank_of(s1) - rank_of(s2));
}
-/// neighboring_files_bb takes a file or a square as input, and returns a
-/// bitboard representing all squares on the neighboring files.
+/// shift_bb() moves bitboard one step along direction Delta. Mainly for pawns.
-inline Bitboard neighboring_files_bb(File f) {
- return NeighboringFilesBB[f];
-}
+template<Square Delta>
+inline Bitboard shift_bb(Bitboard b) {
-inline Bitboard neighboring_files_bb(Square s) {
- return neighboring_files_bb(square_file(s));
+ 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;
}
-/// 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.
+/// 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.
-inline Bitboard this_and_neighboring_files_bb(File f) {
- return ThisAndNeighboringFilesBB[f];
+inline Bitboard rank_bb(Rank r) {
+ return RankBB[r];
+}
+
+inline Bitboard rank_bb(Square s) {
+ return RankBB[rank_of(s)];
+}
+
+inline Bitboard file_bb(File f) {
+ return FileBB[f];
}
-inline Bitboard this_and_neighboring_files_bb(Square s) {
- return this_and_neighboring_files_bb(square_file(s));
+inline Bitboard file_bb(Square s) {
+ return FileBB[file_of(s)];
}
-/// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
-/// representing all squares on the given rank from the given color's point of
-/// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
-/// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
-/// rank.
+/// adjacent_files_bb() takes a file as input and returns a bitboard representing
+/// all squares on the adjacent files.
-inline Bitboard relative_rank_bb(Color c, Rank r) {
- return RelativeRankBB[c][r];
+inline Bitboard adjacent_files_bb(File f) {
+ return AdjacentFilesBB[f];
}
-/// 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.
+/// 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.
inline Bitboard in_front_bb(Color c, Rank r) {
return InFrontBB[c][r];
}
-inline Bitboard in_front_bb(Color c, Square s) {
- return in_front_bb(c, square_rank(s));
-}
-
-/// behind_bb() takes a color and a rank or square as input, and returns a
-/// bitboard representing all the squares on all ranks behind of the rank
-/// (or square), from the given color's point of view.
+/// 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 behind_bb(Color c, Rank r) {
- return InFrontBB[opposite_color(c)][r];
-}
-
-inline Bitboard behind_bb(Color c, Square s) {
- return in_front_bb(opposite_color(c), square_rank(s));
+inline Bitboard between_bb(Square s1, Square s2) {
+ return BetweenBB[s1][s2];
}
-/// ray_bb() gives a bitboard representing all squares along the ray in a
-/// given direction from a given square.
+/// 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)
-inline Bitboard ray_bb(Square s, SignedDirection d) {
- return RayBB[s][d];
+inline Bitboard forward_bb(Color c, Square s) {
+ return ForwardBB[c][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)
+/// 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);
-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 pawn_attack_span(Color c, Square s) {
+ return PawnAttackSpan[c][s];
}
-inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
- Bitboard b = blockers & BMask[s];
- return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
-}
-#else // if !defined(IS_64BIT)
+/// 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)
-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])];
+inline Bitboard passed_pawn_mask(Color c, Square s) {
+ return PassedPawnMask[c][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])];
-}
-#endif
+/// squares_of_color() returns a bitboard representing all squares with the same
+/// color of the given square.
-inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
- return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
+inline Bitboard squares_of_color(Square s) {
+ return DarkSquares & s ? DarkSquares : ~DarkSquares;
}
-/// 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.
+/// squares_aligned() returns true if the squares s1, s2 and s3 are aligned
+/// either on a straight or on a diagonal line.
-inline Bitboard squares_between(Square s1, Square s2) {
- return BetweenBB[s1][s2];
+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]);
}
-/// 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. For instance,
-/// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
-/// e3, e2 and e1 set.
-
-inline Bitboard squares_in_front_of(Color c, Square s) {
- return in_front_bb(c, s) & file_bb(s);
-}
+/// 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<PieceType Pt>
+FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
+ Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks;
+ Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
+ unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
-/// squares_behind is similar to squares_in_front, but returns the squares
-/// behind the square instead of in front of the square.
+ if (Is64Bit)
+ return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
-inline Bitboard squares_behind(Color c, Square s) {
- return in_front_bb(opposite_color(c), s) & file_bb(s);
+ 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];
}
+template<PieceType Pt>
+inline Bitboard attacks_bb(Square s, Bitboard occ) {
+ return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index<Pt>(s, occ)];
+}
-/// 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.
-inline Bitboard passed_pawn_mask(Color c, Square s) {
- return PassedPawnMask[c][s];
-}
+/// 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.
+#ifdef USE_BSFQ
-/// outpost_mask takes a color and a square as input, and returns a bitboard
-/// mask which can be used to test whether a piece on the square can possibly
-/// be driven away by an enemy pawn.
+# if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
-inline Bitboard outpost_mask(Color c, Square s) {
- return OutpostMask[c][s];
+FORCE_INLINE Square lsb(Bitboard b) {
+ unsigned long index;
+ _BitScanForward64(&index, b);
+ return (Square) index;
}
+FORCE_INLINE Square msb(Bitboard b) {
+ unsigned long index;
+ _BitScanReverse64(&index, b);
+ return (Square) index;
+}
-/// isolated_pawn_mask takes a square as input, and returns a bitboard mask
-/// which can be used to test whether a pawn on the given square is isolated.
+# elif defined(__arm__)
-inline Bitboard isolated_pawn_mask(Square s) {
- return neighboring_files_bb(s);
+FORCE_INLINE int lsb32(uint32_t v) {
+ __asm__("rbit %0, %1" : "=r"(v) : "r"(v));
+ return __builtin_clz(v);
}
+FORCE_INLINE Square msb(Bitboard b) {
+ return (Square) (63 - __builtin_clzll(b));
+}
-/// 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.
+FORCE_INLINE Square lsb(Bitboard b) {
+ return (Square) (uint32_t(b) ? lsb32(uint32_t(b)) : 32 + lsb32(uint32_t(b >> 32)));
+}
-#if defined(USE_BSFQ) // Assembly code by Heinz van Saanen
+# else
-inline Square __attribute__((always_inline)) first_1(Bitboard b) {
- Bitboard dummy;
- __asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
- return (Square)(dummy);
+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;
}
-inline Square __attribute__((always_inline)) pop_1st_bit(Bitboard* b) {
- const Square s = first_1(*b);
- *b &= ~(1ULL<<s);
- return s;
+FORCE_INLINE Square msb(Bitboard b) {
+ Bitboard index;
+ __asm__("bsrq %1, %0": "=r"(index): "rm"(b) );
+ return (Square) index;
}
-#else // if !defined(USE_BSFQ)
+# endif
-inline Square first_1(Bitboard b) {
- b ^= (b - 1);
- uint32_t fold = int(b) ^ int(b >> 32);
- return Square(BitTable[(fold * 0x783a9b23) >> 26]);
+FORCE_INLINE Square pop_lsb(Bitboard* b) {
+ const Square s = lsb(*b);
+ *b &= *b - 1;
+ return s;
}
-extern Square pop_1st_bit(Bitboard* b);
-
-#endif
+#else // if defined(USE_BSFQ)
+extern Square msb(Bitboard b);
+extern Square lsb(Bitboard b);
+extern Square pop_lsb(Bitboard* b);
-////
-//// Prototypes
-////
+#endif
-extern void print_bitboard(Bitboard b);
-extern void init_bitboards();
+/// frontmost_sq() and backmost_sq() find the square corresponding to the
+/// most/least advanced bit relative to the given color.
+inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
+inline Square backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(b); }
-#endif // !defined(BITBOARD_H_INCLUDED)
+#endif // #ifndef BITBOARD_H_INCLUDED
projects / stockfish / blobdiff