2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
12 Stockfish is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #if !defined(BITBOARD_H_INCLUDED)
22 #define BITBOARD_H_INCLUDED
29 extern void print(Bitboard b);
35 extern Bitboard RMasks[64];
36 extern Bitboard RMagics[64];
37 extern Bitboard* RAttacks[64];
38 extern unsigned RShifts[64];
40 extern Bitboard BMasks[64];
41 extern Bitboard BMagics[64];
42 extern Bitboard* BAttacks[64];
43 extern unsigned BShifts[64];
45 extern Bitboard SquareBB[64];
46 extern Bitboard FileBB[8];
47 extern Bitboard RankBB[8];
48 extern Bitboard AdjacentFilesBB[8];
49 extern Bitboard ThisAndAdjacentFilesBB[8];
50 extern Bitboard InFrontBB[2][8];
51 extern Bitboard StepAttacksBB[16][64];
52 extern Bitboard BetweenBB[64][64];
53 extern Bitboard SquaresInFrontMask[2][64];
54 extern Bitboard PassedPawnMask[2][64];
55 extern Bitboard AttackSpanMask[2][64];
56 extern Bitboard PseudoAttacks[6][64];
59 /// Overloads of bitwise operators between a Bitboard and a Square for testing
60 /// whether a given bit is set in a bitboard, and for setting and clearing bits.
62 inline Bitboard operator&(Bitboard b, Square s) {
63 return b & SquareBB[s];
66 inline Bitboard& operator|=(Bitboard& b, Square s) {
67 return b |= SquareBB[s];
70 inline Bitboard& operator^=(Bitboard& b, Square s) {
71 return b ^= SquareBB[s];
74 inline Bitboard operator|(Bitboard b, Square s) {
75 return b | SquareBB[s];
78 inline Bitboard operator^(Bitboard b, Square s) {
79 return b ^ SquareBB[s];
83 /// rank_bb() and file_bb() take a file or a square as input and return
84 /// a bitboard representing all squares on the given file or rank.
86 inline Bitboard rank_bb(Rank r) {
90 inline Bitboard rank_bb(Square s) {
91 return RankBB[rank_of(s)];
94 inline Bitboard file_bb(File f) {
98 inline Bitboard file_bb(Square s) {
99 return FileBB[file_of(s)];
103 /// adjacent_files_bb takes a file as input and returns a bitboard representing
104 /// all squares on the adjacent files.
106 inline Bitboard adjacent_files_bb(File f) {
107 return AdjacentFilesBB[f];
111 /// this_and_adjacent_files_bb takes a file as input and returns a bitboard
112 /// representing all squares on the given and adjacent files.
114 inline Bitboard this_and_adjacent_files_bb(File f) {
115 return ThisAndAdjacentFilesBB[f];
119 /// in_front_bb() takes a color and a rank or square as input, and returns a
120 /// bitboard representing all the squares on all ranks in front of the rank
121 /// (or square), from the given color's point of view. For instance,
122 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
123 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
125 inline Bitboard in_front_bb(Color c, Rank r) {
126 return InFrontBB[c][r];
129 inline Bitboard in_front_bb(Color c, Square s) {
130 return InFrontBB[c][rank_of(s)];
134 /// Functions for computing sliding attack bitboards. Function attacks_bb() takes
135 /// a square and a bitboard of occupied squares as input, and returns a bitboard
136 /// representing all squares attacked by Pt (bishop or rook) on the given square.
137 template<PieceType Pt>
138 FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
140 Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks;
141 Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
142 unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
145 return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
147 unsigned lo = unsigned(occ) & unsigned(Masks[s]);
148 unsigned hi = unsigned(occ >> 32) & unsigned(Masks[s] >> 32);
149 return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
152 template<PieceType Pt>
153 inline Bitboard attacks_bb(Square s, Bitboard occ) {
154 Bitboard** const Attacks = Pt == ROOK ? RAttacks : BAttacks;
155 return Attacks[s][magic_index<Pt>(s, occ)];
159 /// squares_between returns a bitboard representing all squares between
160 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
161 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
162 /// on the same line, file or diagonal, EmptyBoardBB is returned.
164 inline Bitboard squares_between(Square s1, Square s2) {
165 return BetweenBB[s1][s2];
169 /// squares_in_front_of takes a color and a square as input, and returns a
170 /// bitboard representing all squares along the line in front of the square,
171 /// from the point of view of the given color. Definition of the table is:
172 /// SquaresInFrontOf[c][s] = in_front_bb(c, s) & file_bb(s)
174 inline Bitboard squares_in_front_of(Color c, Square s) {
175 return SquaresInFrontMask[c][s];
179 /// passed_pawn_mask takes a color and a square as input, and returns a
180 /// bitboard mask which can be used to test if a pawn of the given color on
181 /// the given square is a passed pawn. Definition of the table is:
182 /// PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(s)
184 inline Bitboard passed_pawn_mask(Color c, Square s) {
185 return PassedPawnMask[c][s];
189 /// attack_span_mask takes a color and a square as input, and returns a bitboard
190 /// representing all squares that can be attacked by a pawn of the given color
191 /// when it moves along its file starting from the given square. Definition is:
192 /// AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
194 inline Bitboard attack_span_mask(Color c, Square s) {
195 return AttackSpanMask[c][s];
199 /// squares_aligned returns true if the squares s1, s2 and s3 are aligned
200 /// either on a straight or on a diagonal line.
202 inline bool squares_aligned(Square s1, Square s2, Square s3) {
203 return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
204 & ( SquareBB[s1] | SquareBB[s2] | SquareBB[s3]);
208 /// same_color_squares() returns a bitboard representing all squares with
209 /// the same color of the given square.
211 inline Bitboard same_color_squares(Square s) {
212 return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL
213 : ~0xAA55AA55AA55AA55ULL;
217 /// single_bit() returns true if in the 'b' bitboard is set a single bit (or if
220 inline bool single_bit(Bitboard b) {
221 return !(b & (b - 1));
225 /// first_1() finds the least significant nonzero bit in a nonzero bitboard.
226 /// pop_1st_bit() finds and clears the least significant nonzero bit in a
227 /// nonzero bitboard.
229 #if defined(USE_BSFQ)
231 #if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
233 FORCE_INLINE Square first_1(Bitboard b) {
235 _BitScanForward64(&index, b);
236 return (Square) index;
239 FORCE_INLINE Square last_1(Bitboard b) {
241 _BitScanReverse64(&index, b);
242 return (Square) index;
246 FORCE_INLINE Square first_1(Bitboard b) { // Assembly code by Heinz van Saanen
248 __asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
249 return (Square) dummy;
252 FORCE_INLINE Square last_1(Bitboard b) {
254 __asm__("bsrq %1, %0": "=r"(dummy): "rm"(b) );
255 return (Square) dummy;
259 FORCE_INLINE Square pop_1st_bit(Bitboard* b) {
260 const Square s = first_1(*b);
265 #else // if !defined(USE_BSFQ)
267 extern Square first_1(Bitboard b);
268 extern Square last_1(Bitboard b);
269 extern Square pop_1st_bit(Bitboard* b);
273 #endif // !defined(BITBOARD_H_INCLUDED)