422 lines
11 KiB
C
422 lines
11 KiB
C
/*
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Glaurung, a UCI chess playing engine.
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Copyright (C) 2004-2008 Tord Romstad
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Glaurung 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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Glaurung 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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////
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//// Defines
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////
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//#define USE_COMPACT_ROOK_ATTACKS
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//#define USE_32BIT_ATTACKS
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#define USE_FOLDED_BITSCAN
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#define BITCOUNT_SWAR_64
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//#define BITCOUNT_SWAR_32
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//#define BITCOUNT_LOOP
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////
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//// Includes
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////
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#include "direction.h"
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#include "piece.h"
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#include "square.h"
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#include "types.h"
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////
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//// Types
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////
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typedef uint64_t Bitboard;
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////
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//// Constants and variables
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////
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const Bitboard EmptyBoardBB = 0ULL;
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const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
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const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
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extern const Bitboard SquaresByColorBB[2];
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const Bitboard FileABB = 0x0101010101010101ULL;
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const Bitboard FileBBB = 0x0202020202020202ULL;
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const Bitboard FileCBB = 0x0404040404040404ULL;
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const Bitboard FileDBB = 0x0808080808080808ULL;
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const Bitboard FileEBB = 0x1010101010101010ULL;
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const Bitboard FileFBB = 0x2020202020202020ULL;
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const Bitboard FileGBB = 0x4040404040404040ULL;
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const Bitboard FileHBB = 0x8080808080808080ULL;
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extern const Bitboard FileBB[8];
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extern const Bitboard NeighboringFilesBB[8];
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extern const Bitboard ThisAndNeighboringFilesBB[8];
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const Bitboard Rank1BB = 0xFFULL;
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const Bitboard Rank2BB = 0xFF00ULL;
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const Bitboard Rank3BB = 0xFF0000ULL;
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const Bitboard Rank4BB = 0xFF000000ULL;
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const Bitboard Rank5BB = 0xFF00000000ULL;
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const Bitboard Rank6BB = 0xFF0000000000ULL;
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const Bitboard Rank7BB = 0xFF000000000000ULL;
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const Bitboard Rank8BB = 0xFF00000000000000ULL;
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extern const Bitboard RankBB[8];
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extern const Bitboard RelativeRankBB[2][8];
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extern const Bitboard InFrontBB[2][8];
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extern Bitboard SetMaskBB[64];
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extern Bitboard ClearMaskBB[64];
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extern Bitboard StepAttackBB[16][64];
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extern Bitboard RayBB[64][8];
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extern Bitboard BetweenBB[64][64];
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extern Bitboard PassedPawnMask[2][64];
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extern Bitboard OutpostMask[2][64];
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#if defined(USE_COMPACT_ROOK_ATTACKS)
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extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
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#else
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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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#endif // defined(USE_COMPACT_ROOK_ATTACKS)
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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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////
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//// Inline functions
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////
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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 set_mask_bb(Square s) {
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// return 1ULL << s;
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return SetMaskBB[s];
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}
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inline Bitboard clear_mask_bb(Square s) {
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// return ~set_mask_bb(s);
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return ClearMaskBB[s];
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}
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inline Bitboard bit_is_set(Bitboard b, Square s) {
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return b & set_mask_bb(s);
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}
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inline void set_bit(Bitboard *b, Square s) {
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*b |= set_mask_bb(s);
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}
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inline void clear_bit(Bitboard *b, Square s) {
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*b &= clear_mask_bb(s);
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}
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/// rank_bb() and file_bb() gives a bitboard containing all squares on a given
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/// file or rank. It is also possible to pass a square as input to these
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/// functions.
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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 rank_bb(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 file_bb(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 neighboring_files_bb(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
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/// returns a bitboard representing all squares on the given and neighboring
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/// 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 this_and_neighboring_files_bb(square_file(s));
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}
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/// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
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/// representing all squares on the given rank from the given color's point of
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/// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
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/// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
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/// rank.
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inline Bitboard relative_rank_bb(Color c, Rank r) {
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return RelativeRankBB[c][r];
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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 in_front_bb(c, square_rank(s));
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}
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/// ray_bb() gives a bitboard representing all squares along the ray in a
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/// given direction from a given square.
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inline Bitboard ray_bb(Square s, SignedDirection d) {
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return RayBB[s][d];
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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(USE_COMPACT_ROOK_ATTACKS)
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inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
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return
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FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
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}
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inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
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Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
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return RankAttacks[square_file(s)][b] & rank_bb(s);
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}
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inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
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return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
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}
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#elif defined(USE_32BIT_ATTACKS)
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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]) ^
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int(b >> 32) * int(RMult[s] >> 32))
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>> RShift[s])];
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}
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#else
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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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#endif
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#if defined(USE_32BIT_ATTACKS)
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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]) ^
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int(b >> 32) * int(BMult[s] >> 32))
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>> BShift[s])];
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}
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#else // defined(USE_32BIT_ATTACKS)
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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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#endif // defined(USE_32BIT_ATTACKS)
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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. For instance,
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/// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
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/// e3, e2 and e1 set.
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inline Bitboard squares_in_front_of(Color c, Square s) {
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return in_front_bb(c, s) & file_bb(s);
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}
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/// squares_behind is similar to squares_in_front, but returns the squares
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/// behind the square instead of in front of the square.
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inline Bitboard squares_behind(Color c, Square s) {
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return in_front_bb(opposite_color(c), s) & file_bb(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.
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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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/// outpost_mask takes a color and a square as input, and returns a bitboard
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/// mask which can be used to test whether a piece on the square can possibly
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/// be driven away by an enemy pawn.
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inline Bitboard outpost_mask(Color c, Square s) {
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return OutpostMask[c][s];
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}
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/// isolated_pawn_mask takes a square as input, and returns a bitboard mask
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/// which can be used to test whether a pawn on the given square is isolated.
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inline Bitboard isolated_pawn_mask(Square s) {
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return neighboring_files_bb(s);
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}
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/// count_1s() counts the number of nonzero bits in a bitboard.
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#if defined(BITCOUNT_LOOP)
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inline int count_1s(Bitboard b) {
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int r;
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for(r = 0; b; r++, b &= b - 1);
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return r;
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}
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inline int count_1s_max_15(Bitboard b) {
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return count_1s(b);
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}
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#elif defined(BITCOUNT_SWAR_32)
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inline int count_1s(Bitboard b) {
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unsigned w = unsigned(b >> 32), v = unsigned(b);
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v = v - ((v >> 1) & 0x55555555);
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w = w - ((w >> 1) & 0x55555555);
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v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
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w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
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v = (v + (v >> 4)) & 0x0F0F0F0F;
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w = (w + (w >> 4)) & 0x0F0F0F0F;
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v = ((v+w) * 0x01010101) >> 24; // mul is fast on amd procs
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return int(v);
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}
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inline int count_1s_max_15(Bitboard b) {
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unsigned w = unsigned(b >> 32), v = unsigned(b);
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v = v - ((v >> 1) & 0x55555555);
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w = w - ((w >> 1) & 0x55555555);
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v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
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w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
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v = ((v+w) * 0x11111111) >> 28;
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return int(v);
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}
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#elif defined(BITCOUNT_SWAR_64)
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inline int count_1s(Bitboard b) {
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b -= ((b>>1) & 0x5555555555555555ULL);
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b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
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b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
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b *= 0x0101010101010101ULL;
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return int(b >> 56);
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}
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inline int count_1s_max_15(Bitboard b) {
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b -= (b>>1) & 0x5555555555555555ULL;
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b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
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b *= 0x1111111111111111ULL;
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return int(b >> 60);
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}
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#endif // BITCOUNT
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////
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//// Prototypes
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////
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extern void print_bitboard(Bitboard b);
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extern void init_bitboards();
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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 // !defined(BITBOARD_H_INCLUDED)
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