2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2009 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.
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/>.
22 #if !defined(BITBOARD_H_INCLUDED)
23 #define BITBOARD_H_INCLUDED
29 // Comment following define if you prefer manually adjust
30 // platform macros defined below
31 #define AUTO_CONFIGURATION
33 // Quiet a warning on Intel compiler
34 #if !defined(__SIZEOF_INT__ )
35 #define __SIZEOF_INT__ 0
38 // Check for 64 bits for different compilers: Intel, MSVC and gcc
39 #if defined(__x86_64) || defined(_WIN64) || (__SIZEOF_INT__ > 4)
43 #if !defined(AUTO_CONFIGURATION) || defined(IS_64BIT)
45 //#define USE_COMPACT_ROOK_ATTACKS
46 //#define USE_32BIT_ATTACKS
47 #define USE_FOLDED_BITSCAN
51 #define USE_32BIT_ATTACKS
52 #define USE_FOLDED_BITSCAN
60 #include "direction.h"
70 typedef uint64_t Bitboard;
74 //// Constants and variables
77 const Bitboard EmptyBoardBB = 0ULL;
79 const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
80 const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
81 const Bitboard SquaresByColorBB[2] = { BlackSquaresBB, WhiteSquaresBB };
83 const Bitboard FileABB = 0x0101010101010101ULL;
84 const Bitboard FileBBB = 0x0202020202020202ULL;
85 const Bitboard FileCBB = 0x0404040404040404ULL;
86 const Bitboard FileDBB = 0x0808080808080808ULL;
87 const Bitboard FileEBB = 0x1010101010101010ULL;
88 const Bitboard FileFBB = 0x2020202020202020ULL;
89 const Bitboard FileGBB = 0x4040404040404040ULL;
90 const Bitboard FileHBB = 0x8080808080808080ULL;
92 const Bitboard FileBB[8] = {
93 FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB
96 const Bitboard NeighboringFilesBB[8] = {
97 FileBBB, FileABB|FileCBB, FileBBB|FileDBB, FileCBB|FileEBB,
98 FileDBB|FileFBB, FileEBB|FileGBB, FileFBB|FileHBB, FileGBB
101 const Bitboard ThisAndNeighboringFilesBB[8] = {
102 FileABB|FileBBB, FileABB|FileBBB|FileCBB,
103 FileBBB|FileCBB|FileDBB, FileCBB|FileDBB|FileEBB,
104 FileDBB|FileEBB|FileFBB, FileEBB|FileFBB|FileGBB,
105 FileFBB|FileGBB|FileHBB, FileGBB|FileHBB
108 const Bitboard Rank1BB = 0xFFULL;
109 const Bitboard Rank2BB = 0xFF00ULL;
110 const Bitboard Rank3BB = 0xFF0000ULL;
111 const Bitboard Rank4BB = 0xFF000000ULL;
112 const Bitboard Rank5BB = 0xFF00000000ULL;
113 const Bitboard Rank6BB = 0xFF0000000000ULL;
114 const Bitboard Rank7BB = 0xFF000000000000ULL;
115 const Bitboard Rank8BB = 0xFF00000000000000ULL;
117 const Bitboard RankBB[8] = {
118 Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB
121 const Bitboard RelativeRankBB[2][8] = {
122 { Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB },
123 { Rank8BB, Rank7BB, Rank6BB, Rank5BB, Rank4BB, Rank3BB, Rank2BB, Rank1BB }
126 const Bitboard InFrontBB[2][8] = {
127 { Rank2BB | Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
128 Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
129 Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
130 Rank5BB | Rank6BB | Rank7BB | Rank8BB,
131 Rank6BB | Rank7BB | Rank8BB,
139 Rank3BB | Rank2BB | Rank1BB,
140 Rank4BB | Rank3BB | Rank2BB | Rank1BB,
141 Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
142 Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
143 Rank7BB | Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB
147 extern Bitboard SetMaskBB[65];
148 extern Bitboard ClearMaskBB[65];
150 extern Bitboard StepAttackBB[16][64];
151 extern Bitboard RayBB[64][8];
152 extern Bitboard BetweenBB[64][64];
154 extern Bitboard PassedPawnMask[2][64];
155 extern Bitboard OutpostMask[2][64];
157 #if defined(USE_COMPACT_ROOK_ATTACKS)
159 extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
163 extern const uint64_t RMult[64];
164 extern const int RShift[64];
165 extern Bitboard RMask[64];
166 extern int RAttackIndex[64];
167 extern Bitboard RAttacks[0x19000];
169 #endif // defined(USE_COMPACT_ROOK_ATTACKS)
171 extern const uint64_t BMult[64];
172 extern const int BShift[64];
173 extern Bitboard BMask[64];
174 extern int BAttackIndex[64];
175 extern Bitboard BAttacks[0x1480];
177 extern Bitboard BishopPseudoAttacks[64];
178 extern Bitboard RookPseudoAttacks[64];
179 extern Bitboard QueenPseudoAttacks[64];
183 //// Inline functions
186 /// Functions for testing whether a given bit is set in a bitboard, and for
187 /// setting and clearing bits.
189 inline Bitboard bit_is_set(Bitboard b, Square s) {
190 return b & SetMaskBB[s];
193 inline void set_bit(Bitboard *b, Square s) {
197 inline void clear_bit(Bitboard *b, Square s) {
198 *b &= ClearMaskBB[s];
202 /// Functions used to update a bitboard after a move. This is faster
203 /// then calling a sequence of clear_bit() + set_bit()
205 inline Bitboard make_move_bb(Square from, Square to) {
206 return SetMaskBB[from] | SetMaskBB[to];
209 inline void do_move_bb(Bitboard *b, Bitboard move_bb) {
213 /// rank_bb() and file_bb() gives a bitboard containing all squares on a given
214 /// file or rank. It is also possible to pass a square as input to these
217 inline Bitboard rank_bb(Rank r) {
221 inline Bitboard rank_bb(Square s) {
222 return rank_bb(square_rank(s));
225 inline Bitboard file_bb(File f) {
229 inline Bitboard file_bb(Square s) {
230 return file_bb(square_file(s));
234 /// neighboring_files_bb takes a file or a square as input, and returns a
235 /// bitboard representing all squares on the neighboring files.
237 inline Bitboard neighboring_files_bb(File f) {
238 return NeighboringFilesBB[f];
241 inline Bitboard neighboring_files_bb(Square s) {
242 return neighboring_files_bb(square_file(s));
246 /// this_and_neighboring_files_bb takes a file or a square as input, and
247 /// returns a bitboard representing all squares on the given and neighboring
250 inline Bitboard this_and_neighboring_files_bb(File f) {
251 return ThisAndNeighboringFilesBB[f];
254 inline Bitboard this_and_neighboring_files_bb(Square s) {
255 return this_and_neighboring_files_bb(square_file(s));
259 /// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
260 /// representing all squares on the given rank from the given color's point of
261 /// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
262 /// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
265 inline Bitboard relative_rank_bb(Color c, Rank r) {
266 return RelativeRankBB[c][r];
270 /// in_front_bb() takes a color and a rank or square as input, and returns a
271 /// bitboard representing all the squares on all ranks in front of the rank
272 /// (or square), from the given color's point of view. For instance,
273 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
274 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
276 inline Bitboard in_front_bb(Color c, Rank r) {
277 return InFrontBB[c][r];
280 inline Bitboard in_front_bb(Color c, Square s) {
281 return in_front_bb(c, square_rank(s));
285 /// behind_bb() takes a color and a rank or square as input, and returns a
286 /// bitboard representing all the squares on all ranks behind of the rank
287 /// (or square), from the given color's point of view.
289 inline Bitboard behind_bb(Color c, Rank r) {
290 return InFrontBB[opposite_color(c)][r];
293 inline Bitboard behind_bb(Color c, Square s) {
294 return in_front_bb(opposite_color(c), square_rank(s));
298 /// ray_bb() gives a bitboard representing all squares along the ray in a
299 /// given direction from a given square.
301 inline Bitboard ray_bb(Square s, SignedDirection d) {
306 /// Functions for computing sliding attack bitboards. rook_attacks_bb(),
307 /// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
308 /// bitboard of occupied squares as input, and return a bitboard representing
309 /// all squares attacked by a rook, bishop or queen on the given square.
311 #if defined(USE_COMPACT_ROOK_ATTACKS)
313 inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
314 Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
316 FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
319 inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
320 Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
321 return RankAttacks[square_file(s)][b] & rank_bb(s);
324 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
325 return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
328 #elif defined(USE_32BIT_ATTACKS)
330 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
331 Bitboard b = blockers & RMask[s];
332 return RAttacks[RAttackIndex[s] +
333 (unsigned(int(b) * int(RMult[s]) ^
334 int(b >> 32) * int(RMult[s] >> 32))
340 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
341 Bitboard b = blockers & RMask[s];
342 return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
347 #if defined(USE_32BIT_ATTACKS)
349 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
350 Bitboard b = blockers & BMask[s];
351 return BAttacks[BAttackIndex[s] +
352 (unsigned(int(b) * int(BMult[s]) ^
353 int(b >> 32) * int(BMult[s] >> 32))
357 #else // defined(USE_32BIT_ATTACKS)
359 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
360 Bitboard b = blockers & BMask[s];
361 return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
364 #endif // defined(USE_32BIT_ATTACKS)
366 inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
367 return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
371 /// squares_between returns a bitboard representing all squares between
372 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
373 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
374 /// on the same line, file or diagonal, EmptyBoardBB is returned.
376 inline Bitboard squares_between(Square s1, Square s2) {
377 return BetweenBB[s1][s2];
381 /// squares_in_front_of takes a color and a square as input, and returns a
382 /// bitboard representing all squares along the line in front of the square,
383 /// from the point of view of the given color. For instance,
384 /// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
385 /// e3, e2 and e1 set.
387 inline Bitboard squares_in_front_of(Color c, Square s) {
388 return in_front_bb(c, s) & file_bb(s);
392 /// squares_behind is similar to squares_in_front, but returns the squares
393 /// behind the square instead of in front of the square.
395 inline Bitboard squares_behind(Color c, Square s) {
396 return in_front_bb(opposite_color(c), s) & file_bb(s);
400 /// passed_pawn_mask takes a color and a square as input, and returns a
401 /// bitboard mask which can be used to test if a pawn of the given color on
402 /// the given square is a passed pawn.
404 inline Bitboard passed_pawn_mask(Color c, Square s) {
405 return PassedPawnMask[c][s];
409 /// outpost_mask takes a color and a square as input, and returns a bitboard
410 /// mask which can be used to test whether a piece on the square can possibly
411 /// be driven away by an enemy pawn.
413 inline Bitboard outpost_mask(Color c, Square s) {
414 return OutpostMask[c][s];
418 /// isolated_pawn_mask takes a square as input, and returns a bitboard mask
419 /// which can be used to test whether a pawn on the given square is isolated.
421 inline Bitboard isolated_pawn_mask(Square s) {
422 return neighboring_files_bb(s);
430 extern void print_bitboard(Bitboard b);
431 extern void init_bitboards();
432 extern Square first_1(Bitboard b);
433 extern Square pop_1st_bit(Bitboard *b);
436 #endif // !defined(BITBOARD_H_INCLUDED)