mirror of
https://github.com/peterosterlund2/droidfish.git
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296 lines
8.7 KiB
C
296 lines
8.7 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) 2008-2010 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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const Bitboard EmptyBoardBB = 0;
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const Bitboard FileABB = 0x0101010101010101ULL;
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const Bitboard FileBBB = FileABB << 1;
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const Bitboard FileCBB = FileABB << 2;
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const Bitboard FileDBB = FileABB << 3;
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const Bitboard FileEBB = FileABB << 4;
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const Bitboard FileFBB = FileABB << 5;
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const Bitboard FileGBB = FileABB << 6;
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const Bitboard FileHBB = FileABB << 7;
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const Bitboard Rank1BB = 0xFF;
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const Bitboard Rank2BB = Rank1BB << (8 * 1);
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const Bitboard Rank3BB = Rank1BB << (8 * 2);
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const Bitboard Rank4BB = Rank1BB << (8 * 3);
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const Bitboard Rank5BB = Rank1BB << (8 * 4);
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const Bitboard Rank6BB = Rank1BB << (8 * 5);
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const Bitboard Rank7BB = Rank1BB << (8 * 6);
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const Bitboard Rank8BB = Rank1BB << (8 * 7);
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extern Bitboard SquaresByColorBB[2];
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extern Bitboard FileBB[8];
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extern Bitboard NeighboringFilesBB[8];
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extern Bitboard ThisAndNeighboringFilesBB[8];
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extern Bitboard RankBB[8];
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extern Bitboard InFrontBB[2][8];
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extern Bitboard SetMaskBB[65];
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extern Bitboard ClearMaskBB[65];
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extern Bitboard StepAttacksBB[16][64];
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extern Bitboard BetweenBB[64][64];
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extern Bitboard SquaresInFrontMask[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 const uint64_t RMult[64];
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extern const int RShift[64];
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extern Bitboard RMask[64];
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extern int RAttackIndex[64];
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extern Bitboard RAttacks[0x19000];
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extern const uint64_t BMult[64];
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extern const int BShift[64];
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extern Bitboard BMask[64];
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extern int BAttackIndex[64];
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extern Bitboard BAttacks[0x1480];
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extern Bitboard BishopPseudoAttacks[64];
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extern Bitboard RookPseudoAttacks[64];
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extern Bitboard QueenPseudoAttacks[64];
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extern uint8_t BitCount8Bit[256];
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/// Functions for testing whether a given bit is set in a bitboard, and for
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/// setting and clearing bits.
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inline Bitboard bit_is_set(Bitboard b, Square s) {
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return b & SetMaskBB[s];
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}
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inline void set_bit(Bitboard *b, Square s) {
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*b |= SetMaskBB[s];
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}
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inline void clear_bit(Bitboard *b, Square s) {
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*b &= ClearMaskBB[s];
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}
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/// Functions used to update a bitboard after a move. This is faster
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/// then calling a sequence of clear_bit() + set_bit()
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inline Bitboard make_move_bb(Square from, Square to) {
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return SetMaskBB[from] | SetMaskBB[to];
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}
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inline void do_move_bb(Bitboard *b, Bitboard move_bb) {
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*b ^= move_bb;
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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[square_rank(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[square_file(s)];
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}
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/// neighboring_files_bb takes a file or a square as input and returns a
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/// bitboard representing all squares on the neighboring files.
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inline Bitboard neighboring_files_bb(File f) {
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return NeighboringFilesBB[f];
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}
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inline Bitboard neighboring_files_bb(Square s) {
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return NeighboringFilesBB[square_file(s)];
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}
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/// this_and_neighboring_files_bb takes a file or a square as input and returns
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/// a bitboard representing all squares on the given and neighboring files.
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inline Bitboard this_and_neighboring_files_bb(File f) {
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return ThisAndNeighboringFilesBB[f];
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}
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inline Bitboard this_and_neighboring_files_bb(Square s) {
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return ThisAndNeighboringFilesBB[square_file(s)];
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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][square_rank(s)];
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}
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/// Functions for computing sliding attack bitboards. rook_attacks_bb(),
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/// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
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/// bitboard of occupied squares as input, and return a bitboard representing
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/// all squares attacked by a rook, bishop or queen on the given square.
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#if defined(IS_64BIT)
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inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = blockers & RMask[s];
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return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
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}
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inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = blockers & BMask[s];
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return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
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}
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#else // if !defined(IS_64BIT)
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inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = blockers & RMask[s];
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return RAttacks[RAttackIndex[s] +
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(unsigned(int(b) * int(RMult[s]) ^ int(b >> 32) * int(RMult[s] >> 32)) >> RShift[s])];
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}
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inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = blockers & BMask[s];
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return BAttacks[BAttackIndex[s] +
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(unsigned(int(b) * int(BMult[s]) ^ int(b >> 32) * int(BMult[s] >> 32)) >> BShift[s])];
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}
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#endif
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inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
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return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
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}
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/// squares_between returns a bitboard representing all squares between
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/// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
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/// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
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/// on the same line, file or diagonal, EmptyBoardBB is returned.
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inline Bitboard squares_between(Square s1, Square s2) {
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return BetweenBB[s1][s2];
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}
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/// squares_in_front_of takes a color and a square as input, and returns a
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/// bitboard representing all squares along the line in front of the square,
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/// from the point of view of the given color. Definition of the table is:
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/// SquaresInFrontOf[c][s] = in_front_bb(c, s) & file_bb(s)
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inline Bitboard squares_in_front_of(Color c, Square s) {
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return SquaresInFrontMask[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_neighboring_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) & neighboring_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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& ((1ULL << s1) | (1ULL << s2) | (1ULL << s3));
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}
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/// first_1() finds the least significant nonzero bit in a nonzero bitboard.
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/// pop_1st_bit() finds and clears the least significant nonzero bit in a
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/// 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 first_1(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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#else
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FORCE_INLINE Square first_1(Bitboard b) { // Assembly code by Heinz van Saanen
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Bitboard dummy;
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__asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
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return (Square) dummy;
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}
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#endif
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FORCE_INLINE Square pop_1st_bit(Bitboard* b) {
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const Square s = first_1(*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 first_1(Bitboard b);
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extern Square pop_1st_bit(Bitboard* b);
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#endif
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extern void print_bitboard(Bitboard b);
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extern void init_bitboards();
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#endif // !defined(BITBOARD_H_INCLUDED)
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