mirror of
https://github.com/peterosterlund2/droidfish.git
synced 2025-01-08 08:17:01 +01:00
281 lines
7.8 KiB
C++
281 lines
7.8 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if !defined(BITBOARD_H_INCLUDED)
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#define BITBOARD_H_INCLUDED
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#include "types.h"
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namespace Bitboards {
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void init();
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void print(Bitboard b);
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}
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namespace Bitbases {
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void init_kpk();
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uint32_t probe_kpk(Square wksq, Square wpsq, Square bksq, Color stm);
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}
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CACHE_LINE_ALIGNMENT
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extern Bitboard RMasks[64];
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extern Bitboard RMagics[64];
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extern Bitboard* RAttacks[64];
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extern unsigned RShifts[64];
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extern Bitboard BMasks[64];
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extern Bitboard BMagics[64];
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extern Bitboard* BAttacks[64];
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extern unsigned BShifts[64];
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extern Bitboard SquareBB[64];
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extern Bitboard FileBB[8];
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extern Bitboard RankBB[8];
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extern Bitboard AdjacentFilesBB[8];
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extern Bitboard ThisAndAdjacentFilesBB[8];
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extern Bitboard InFrontBB[2][8];
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extern Bitboard StepAttacksBB[16][64];
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extern Bitboard BetweenBB[64][64];
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extern Bitboard DistanceRingsBB[64][8];
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extern Bitboard ForwardBB[2][64];
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extern Bitboard PassedPawnMask[2][64];
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extern Bitboard AttackSpanMask[2][64];
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extern Bitboard PseudoAttacks[6][64];
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/// Overloads of bitwise operators between a Bitboard and a Square for testing
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/// whether a given bit is set in a bitboard, and for setting and clearing bits.
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inline Bitboard operator&(Bitboard b, Square s) {
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return b & SquareBB[s];
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}
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inline Bitboard& operator|=(Bitboard& b, Square s) {
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return b |= SquareBB[s];
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}
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inline Bitboard& operator^=(Bitboard& b, Square s) {
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return b ^= SquareBB[s];
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}
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inline Bitboard operator|(Bitboard b, Square s) {
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return b | SquareBB[s];
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}
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inline Bitboard operator^(Bitboard b, Square s) {
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return b ^ SquareBB[s];
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}
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/// more_than_one() returns true if in 'b' there is more than one bit set
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inline bool more_than_one(Bitboard b) {
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return b & (b - 1);
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}
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/// rank_bb() and file_bb() take a file or a square as input and return
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/// a bitboard representing all squares on the given file or rank.
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inline Bitboard rank_bb(Rank r) {
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return RankBB[r];
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}
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inline Bitboard rank_bb(Square s) {
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return RankBB[rank_of(s)];
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}
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inline Bitboard file_bb(File f) {
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return FileBB[f];
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}
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inline Bitboard file_bb(Square s) {
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return FileBB[file_of(s)];
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}
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/// adjacent_files_bb takes a file as input and returns a bitboard representing
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/// all squares on the adjacent files.
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inline Bitboard adjacent_files_bb(File f) {
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return AdjacentFilesBB[f];
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}
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/// this_and_adjacent_files_bb takes a file as input and returns a bitboard
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/// representing all squares on the given and adjacent files.
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inline Bitboard this_and_adjacent_files_bb(File f) {
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return ThisAndAdjacentFilesBB[f];
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}
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/// in_front_bb() takes a color and a rank or square as input, and returns a
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/// bitboard representing all the squares on all ranks in front of the rank
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/// (or square), from the given color's point of view. For instance,
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/// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
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/// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
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inline Bitboard in_front_bb(Color c, Rank r) {
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return InFrontBB[c][r];
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}
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inline Bitboard in_front_bb(Color c, Square s) {
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return InFrontBB[c][rank_of(s)];
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}
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/// between_bb returns a bitboard representing all squares between two squares.
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/// For instance, between_bb(SQ_C4, SQ_F7) returns a bitboard with the bits for
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/// square d5 and e6 set. If s1 and s2 are not on the same line, file or diagonal,
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/// 0 is returned.
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inline Bitboard between_bb(Square s1, Square s2) {
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return BetweenBB[s1][s2];
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}
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/// forward_bb takes a color and a square as input, and returns a bitboard
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/// representing all squares along the line in front of the square, from the
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/// point of view of the given color. Definition of the table is:
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/// ForwardBB[c][s] = in_front_bb(c, s) & file_bb(s)
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inline Bitboard forward_bb(Color c, Square s) {
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return ForwardBB[c][s];
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}
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/// passed_pawn_mask takes a color and a square as input, and returns a
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/// bitboard mask which can be used to test if a pawn of the given color on
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/// the given square is a passed pawn. Definition of the table is:
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/// PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(s)
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inline Bitboard passed_pawn_mask(Color c, Square s) {
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return PassedPawnMask[c][s];
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}
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/// attack_span_mask takes a color and a square as input, and returns a bitboard
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/// representing all squares that can be attacked by a pawn of the given color
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/// when it moves along its file starting from the given square. Definition is:
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/// AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
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inline Bitboard attack_span_mask(Color c, Square s) {
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return AttackSpanMask[c][s];
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}
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/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
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/// either on a straight or on a diagonal line.
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inline bool squares_aligned(Square s1, Square s2, Square s3) {
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return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
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& ( SquareBB[s1] | SquareBB[s2] | SquareBB[s3]);
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}
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/// same_color_squares() returns a bitboard representing all squares with
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/// the same color of the given square.
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inline Bitboard same_color_squares(Square s) {
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return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL
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: ~0xAA55AA55AA55AA55ULL;
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}
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/// Functions for computing sliding attack bitboards. Function attacks_bb() takes
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/// a square and a bitboard of occupied squares as input, and returns a bitboard
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/// representing all squares attacked by Pt (bishop or rook) on the given square.
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template<PieceType Pt>
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FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
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Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks;
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Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
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unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
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if (Is64Bit)
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return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
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unsigned lo = unsigned(occ) & unsigned(Masks[s]);
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unsigned hi = unsigned(occ >> 32) & unsigned(Masks[s] >> 32);
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return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
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}
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template<PieceType Pt>
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inline Bitboard attacks_bb(Square s, Bitboard occ) {
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return (Pt == ROOK ? RAttacks : BAttacks)[s][magic_index<Pt>(s, occ)];
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}
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/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
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/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
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#if defined(USE_BSFQ)
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# if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
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FORCE_INLINE Square lsb(Bitboard b) {
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unsigned long index;
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_BitScanForward64(&index, b);
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return (Square) index;
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}
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FORCE_INLINE Square msb(Bitboard b) {
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unsigned long index;
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_BitScanReverse64(&index, b);
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return (Square) index;
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}
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# else
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FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen
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Bitboard index;
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__asm__("bsfq %1, %0": "=r"(index): "rm"(b) );
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return (Square) index;
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}
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FORCE_INLINE Square msb(Bitboard b) {
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Bitboard index;
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__asm__("bsrq %1, %0": "=r"(index): "rm"(b) );
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return (Square) index;
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}
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# endif
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FORCE_INLINE Square pop_lsb(Bitboard* b) {
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const Square s = lsb(*b);
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*b &= ~(1ULL << s);
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return s;
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}
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#else // if !defined(USE_BSFQ)
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extern Square msb(Bitboard b);
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extern Square lsb(Bitboard b);
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extern Square pop_lsb(Bitboard* b);
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#endif
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#endif // !defined(BITBOARD_H_INCLUDED)
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