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 Marco Costalba
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.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #if !defined(BITBOARD_H_INCLUDED)
22 #define BITBOARD_H_INCLUDED
29 // Comment following define if you prefer manually adjust
30 // platform macros defined below
31 #define AUTO_CONFIGURATION
34 // Check for 64 bits for different compilers: Intel, MSVC and gcc
35 #if defined(__x86_64) || defined(_WIN64) || (__SIZEOF_INT__ > 4)
39 #if !defined(AUTO_CONFIGURATION) || defined(IS_64BIT)
41 //#define USE_COMPACT_ROOK_ATTACKS
42 //#define USE_32BIT_ATTACKS
43 #define USE_FOLDED_BITSCAN
45 #define BITCOUNT_SWAR_64
46 //#define BITCOUNT_SWAR_32
47 //#define BITCOUNT_LOOP
51 #define USE_32BIT_ATTACKS
52 #define USE_FOLDED_BITSCAN
53 #define BITCOUNT_SWAR_32
61 #include "direction.h"
71 typedef uint64_t Bitboard;
75 //// Constants and variables
78 const Bitboard EmptyBoardBB = 0ULL;
80 const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
81 const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
83 extern const Bitboard SquaresByColorBB[2];
85 const Bitboard FileABB = 0x0101010101010101ULL;
86 const Bitboard FileBBB = 0x0202020202020202ULL;
87 const Bitboard FileCBB = 0x0404040404040404ULL;
88 const Bitboard FileDBB = 0x0808080808080808ULL;
89 const Bitboard FileEBB = 0x1010101010101010ULL;
90 const Bitboard FileFBB = 0x2020202020202020ULL;
91 const Bitboard FileGBB = 0x4040404040404040ULL;
92 const Bitboard FileHBB = 0x8080808080808080ULL;
94 extern const Bitboard FileBB[8];
95 extern const Bitboard NeighboringFilesBB[8];
96 extern const Bitboard ThisAndNeighboringFilesBB[8];
98 const Bitboard Rank1BB = 0xFFULL;
99 const Bitboard Rank2BB = 0xFF00ULL;
100 const Bitboard Rank3BB = 0xFF0000ULL;
101 const Bitboard Rank4BB = 0xFF000000ULL;
102 const Bitboard Rank5BB = 0xFF00000000ULL;
103 const Bitboard Rank6BB = 0xFF0000000000ULL;
104 const Bitboard Rank7BB = 0xFF000000000000ULL;
105 const Bitboard Rank8BB = 0xFF00000000000000ULL;
107 extern const Bitboard RankBB[8];
108 extern const Bitboard RelativeRankBB[2][8];
109 extern const Bitboard InFrontBB[2][8];
111 extern Bitboard SetMaskBB[64];
112 extern Bitboard ClearMaskBB[64];
114 extern Bitboard StepAttackBB[16][64];
115 extern Bitboard RayBB[64][8];
116 extern Bitboard BetweenBB[64][64];
118 extern Bitboard PassedPawnMask[2][64];
119 extern Bitboard OutpostMask[2][64];
121 #if defined(USE_COMPACT_ROOK_ATTACKS)
122 extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
124 extern const uint64_t RMult[64];
125 extern const int RShift[64];
126 extern Bitboard RMask[64];
127 extern int RAttackIndex[64];
128 extern Bitboard RAttacks[0x19000];
129 #endif // defined(USE_COMPACT_ROOK_ATTACKS)
131 extern const uint64_t BMult[64];
132 extern const int BShift[64];
133 extern Bitboard BMask[64];
134 extern int BAttackIndex[64];
135 extern Bitboard BAttacks[0x1480];
137 extern Bitboard BishopPseudoAttacks[64];
138 extern Bitboard RookPseudoAttacks[64];
139 extern Bitboard QueenPseudoAttacks[64];
143 //// Inline functions
146 /// Functions for testing whether a given bit is set in a bitboard, and for
147 /// setting and clearing bits.
149 inline Bitboard set_mask_bb(Square s) {
154 inline Bitboard clear_mask_bb(Square s) {
155 // return ~set_mask_bb(s);
156 return ClearMaskBB[s];
159 inline Bitboard bit_is_set(Bitboard b, Square s) {
160 return b & set_mask_bb(s);
163 inline void set_bit(Bitboard *b, Square s) {
164 *b |= set_mask_bb(s);
167 inline void clear_bit(Bitboard *b, Square s) {
168 *b &= clear_mask_bb(s);
172 /// rank_bb() and file_bb() gives a bitboard containing all squares on a given
173 /// file or rank. It is also possible to pass a square as input to these
176 inline Bitboard rank_bb(Rank r) {
180 inline Bitboard rank_bb(Square s) {
181 return rank_bb(square_rank(s));
184 inline Bitboard file_bb(File f) {
188 inline Bitboard file_bb(Square s) {
189 return file_bb(square_file(s));
193 /// neighboring_files_bb takes a file or a square as input, and returns a
194 /// bitboard representing all squares on the neighboring files.
196 inline Bitboard neighboring_files_bb(File f) {
197 return NeighboringFilesBB[f];
200 inline Bitboard neighboring_files_bb(Square s) {
201 return neighboring_files_bb(square_file(s));
205 /// this_and_neighboring_files_bb takes a file or a square as input, and
206 /// returns a bitboard representing all squares on the given and neighboring
209 inline Bitboard this_and_neighboring_files_bb(File f) {
210 return ThisAndNeighboringFilesBB[f];
213 inline Bitboard this_and_neighboring_files_bb(Square s) {
214 return this_and_neighboring_files_bb(square_file(s));
218 /// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
219 /// representing all squares on the given rank from the given color's point of
220 /// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
221 /// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
224 inline Bitboard relative_rank_bb(Color c, Rank r) {
225 return RelativeRankBB[c][r];
229 /// in_front_bb() takes a color and a rank or square as input, and returns a
230 /// bitboard representing all the squares on all ranks in front of the rank
231 /// (or square), from the given color's point of view. For instance,
232 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
233 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
235 inline Bitboard in_front_bb(Color c, Rank r) {
236 return InFrontBB[c][r];
239 inline Bitboard in_front_bb(Color c, Square s) {
240 return in_front_bb(c, square_rank(s));
244 /// ray_bb() gives a bitboard representing all squares along the ray in a
245 /// given direction from a given square.
247 inline Bitboard ray_bb(Square s, SignedDirection d) {
252 /// Functions for computing sliding attack bitboards. rook_attacks_bb(),
253 /// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
254 /// bitboard of occupied squares as input, and return a bitboard representing
255 /// all squares attacked by a rook, bishop or queen on the given square.
257 #if defined(USE_COMPACT_ROOK_ATTACKS)
259 inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
260 Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
262 FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
265 inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
266 Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
267 return RankAttacks[square_file(s)][b] & rank_bb(s);
270 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
271 return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
274 #elif defined(USE_32BIT_ATTACKS)
276 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
277 Bitboard b = blockers & RMask[s];
278 return RAttacks[RAttackIndex[s] +
279 (unsigned(int(b) * int(RMult[s]) ^
280 int(b >> 32) * int(RMult[s] >> 32))
286 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
287 Bitboard b = blockers & RMask[s];
288 return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
293 #if defined(USE_32BIT_ATTACKS)
295 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
296 Bitboard b = blockers & BMask[s];
297 return BAttacks[BAttackIndex[s] +
298 (unsigned(int(b) * int(BMult[s]) ^
299 int(b >> 32) * int(BMult[s] >> 32))
303 #else // defined(USE_32BIT_ATTACKS)
305 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
306 Bitboard b = blockers & BMask[s];
307 return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
310 #endif // defined(USE_32BIT_ATTACKS)
312 inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
313 return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
317 /// squares_between returns a bitboard representing all squares between
318 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
319 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
320 /// on the same line, file or diagonal, EmptyBoardBB is returned.
322 inline Bitboard squares_between(Square s1, Square s2) {
323 return BetweenBB[s1][s2];
327 /// squares_in_front_of takes a color and a square as input, and returns a
328 /// bitboard representing all squares along the line in front of the square,
329 /// from the point of view of the given color. For instance,
330 /// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
331 /// e3, e2 and e1 set.
333 inline Bitboard squares_in_front_of(Color c, Square s) {
334 return in_front_bb(c, s) & file_bb(s);
338 /// squares_behind is similar to squares_in_front, but returns the squares
339 /// behind the square instead of in front of the square.
341 inline Bitboard squares_behind(Color c, Square s) {
342 return in_front_bb(opposite_color(c), s) & file_bb(s);
346 /// passed_pawn_mask takes a color and a square as input, and returns a
347 /// bitboard mask which can be used to test if a pawn of the given color on
348 /// the given square is a passed pawn.
350 inline Bitboard passed_pawn_mask(Color c, Square s) {
351 return PassedPawnMask[c][s];
355 /// outpost_mask takes a color and a square as input, and returns a bitboard
356 /// mask which can be used to test whether a piece on the square can possibly
357 /// be driven away by an enemy pawn.
359 inline Bitboard outpost_mask(Color c, Square s) {
360 return OutpostMask[c][s];
364 /// isolated_pawn_mask takes a square as input, and returns a bitboard mask
365 /// which can be used to test whether a pawn on the given square is isolated.
367 inline Bitboard isolated_pawn_mask(Square s) {
368 return neighboring_files_bb(s);
372 /// count_1s() counts the number of nonzero bits in a bitboard.
374 #if defined(BITCOUNT_LOOP)
376 inline int count_1s(Bitboard b) {
378 for(r = 0; b; r++, b &= b - 1);
382 inline int count_1s_max_15(Bitboard b) {
386 #elif defined(BITCOUNT_SWAR_32)
388 inline int count_1s(Bitboard b) {
389 unsigned w = unsigned(b >> 32), v = unsigned(b);
390 v = v - ((v >> 1) & 0x55555555);
391 w = w - ((w >> 1) & 0x55555555);
392 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
393 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
394 v = (v + (v >> 4)) & 0x0F0F0F0F;
395 w = (w + (w >> 4)) & 0x0F0F0F0F;
396 v = ((v+w) * 0x01010101) >> 24; // mul is fast on amd procs
400 inline int count_1s_max_15(Bitboard b) {
401 unsigned w = unsigned(b >> 32), v = unsigned(b);
402 v = v - ((v >> 1) & 0x55555555);
403 w = w - ((w >> 1) & 0x55555555);
404 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
405 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
406 v = ((v+w) * 0x11111111) >> 28;
410 #elif defined(BITCOUNT_SWAR_64)
412 inline int count_1s(Bitboard b) {
413 b -= ((b>>1) & 0x5555555555555555ULL);
414 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
415 b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
416 b *= 0x0101010101010101ULL;
420 inline int count_1s_max_15(Bitboard b) {
421 b -= (b>>1) & 0x5555555555555555ULL;
422 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
423 b *= 0x1111111111111111ULL;
434 extern void print_bitboard(Bitboard b);
435 extern void init_bitboards();
436 extern Square first_1(Bitboard b);
437 extern Square pop_1st_bit(Bitboard *b);
440 #endif // !defined(BITBOARD_H_INCLUDED)