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
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
49 #define BITCOUNT_SWAR_64
50 //#define BITCOUNT_SWAR_32
51 //#define BITCOUNT_LOOP
55 #define USE_32BIT_ATTACKS
56 #define USE_FOLDED_BITSCAN
57 #define BITCOUNT_SWAR_32
65 #include "direction.h"
75 typedef uint64_t Bitboard;
79 //// Constants and variables
82 const Bitboard EmptyBoardBB = 0ULL;
84 const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
85 const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
87 extern const Bitboard SquaresByColorBB[2];
89 const Bitboard FileABB = 0x0101010101010101ULL;
90 const Bitboard FileBBB = 0x0202020202020202ULL;
91 const Bitboard FileCBB = 0x0404040404040404ULL;
92 const Bitboard FileDBB = 0x0808080808080808ULL;
93 const Bitboard FileEBB = 0x1010101010101010ULL;
94 const Bitboard FileFBB = 0x2020202020202020ULL;
95 const Bitboard FileGBB = 0x4040404040404040ULL;
96 const Bitboard FileHBB = 0x8080808080808080ULL;
98 extern const Bitboard FileBB[8];
99 extern const Bitboard NeighboringFilesBB[8];
100 extern const Bitboard ThisAndNeighboringFilesBB[8];
102 const Bitboard Rank1BB = 0xFFULL;
103 const Bitboard Rank2BB = 0xFF00ULL;
104 const Bitboard Rank3BB = 0xFF0000ULL;
105 const Bitboard Rank4BB = 0xFF000000ULL;
106 const Bitboard Rank5BB = 0xFF00000000ULL;
107 const Bitboard Rank6BB = 0xFF0000000000ULL;
108 const Bitboard Rank7BB = 0xFF000000000000ULL;
109 const Bitboard Rank8BB = 0xFF00000000000000ULL;
111 extern const Bitboard RankBB[8];
112 extern const Bitboard RelativeRankBB[2][8];
113 extern const Bitboard InFrontBB[2][8];
115 extern Bitboard SetMaskBB[64];
116 extern Bitboard ClearMaskBB[64];
118 extern Bitboard StepAttackBB[16][64];
119 extern Bitboard RayBB[64][8];
120 extern Bitboard BetweenBB[64][64];
122 extern Bitboard PassedPawnMask[2][64];
123 extern Bitboard OutpostMask[2][64];
125 #if defined(USE_COMPACT_ROOK_ATTACKS)
126 extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
128 extern const uint64_t RMult[64];
129 extern const int RShift[64];
130 extern Bitboard RMask[64];
131 extern int RAttackIndex[64];
132 extern Bitboard RAttacks[0x19000];
133 #endif // defined(USE_COMPACT_ROOK_ATTACKS)
135 extern const uint64_t BMult[64];
136 extern const int BShift[64];
137 extern Bitboard BMask[64];
138 extern int BAttackIndex[64];
139 extern Bitboard BAttacks[0x1480];
141 extern Bitboard BishopPseudoAttacks[64];
142 extern Bitboard RookPseudoAttacks[64];
143 extern Bitboard QueenPseudoAttacks[64];
147 //// Inline functions
150 /// Functions for testing whether a given bit is set in a bitboard, and for
151 /// setting and clearing bits.
153 inline Bitboard set_mask_bb(Square s) {
158 inline Bitboard clear_mask_bb(Square s) {
159 // return ~set_mask_bb(s);
160 return ClearMaskBB[s];
163 inline Bitboard bit_is_set(Bitboard b, Square s) {
164 return b & set_mask_bb(s);
167 inline void set_bit(Bitboard *b, Square s) {
168 *b |= set_mask_bb(s);
171 inline void clear_bit(Bitboard *b, Square s) {
172 *b &= clear_mask_bb(s);
176 /// rank_bb() and file_bb() gives a bitboard containing all squares on a given
177 /// file or rank. It is also possible to pass a square as input to these
180 inline Bitboard rank_bb(Rank r) {
184 inline Bitboard rank_bb(Square s) {
185 return rank_bb(square_rank(s));
188 inline Bitboard file_bb(File f) {
192 inline Bitboard file_bb(Square s) {
193 return file_bb(square_file(s));
197 /// neighboring_files_bb takes a file or a square as input, and returns a
198 /// bitboard representing all squares on the neighboring files.
200 inline Bitboard neighboring_files_bb(File f) {
201 return NeighboringFilesBB[f];
204 inline Bitboard neighboring_files_bb(Square s) {
205 return neighboring_files_bb(square_file(s));
209 /// this_and_neighboring_files_bb takes a file or a square as input, and
210 /// returns a bitboard representing all squares on the given and neighboring
213 inline Bitboard this_and_neighboring_files_bb(File f) {
214 return ThisAndNeighboringFilesBB[f];
217 inline Bitboard this_and_neighboring_files_bb(Square s) {
218 return this_and_neighboring_files_bb(square_file(s));
222 /// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
223 /// representing all squares on the given rank from the given color's point of
224 /// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
225 /// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
228 inline Bitboard relative_rank_bb(Color c, Rank r) {
229 return RelativeRankBB[c][r];
233 /// in_front_bb() takes a color and a rank or square as input, and returns a
234 /// bitboard representing all the squares on all ranks in front of the rank
235 /// (or square), from the given color's point of view. For instance,
236 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
237 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
239 inline Bitboard in_front_bb(Color c, Rank r) {
240 return InFrontBB[c][r];
243 inline Bitboard in_front_bb(Color c, Square s) {
244 return in_front_bb(c, square_rank(s));
248 /// ray_bb() gives a bitboard representing all squares along the ray in a
249 /// given direction from a given square.
251 inline Bitboard ray_bb(Square s, SignedDirection d) {
256 /// Functions for computing sliding attack bitboards. rook_attacks_bb(),
257 /// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
258 /// bitboard of occupied squares as input, and return a bitboard representing
259 /// all squares attacked by a rook, bishop or queen on the given square.
261 #if defined(USE_COMPACT_ROOK_ATTACKS)
263 inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
264 Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
266 FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
269 inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
270 Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
271 return RankAttacks[square_file(s)][b] & rank_bb(s);
274 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
275 return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
278 #elif defined(USE_32BIT_ATTACKS)
280 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
281 Bitboard b = blockers & RMask[s];
282 return RAttacks[RAttackIndex[s] +
283 (unsigned(int(b) * int(RMult[s]) ^
284 int(b >> 32) * int(RMult[s] >> 32))
290 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
291 Bitboard b = blockers & RMask[s];
292 return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
297 #if defined(USE_32BIT_ATTACKS)
299 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
300 Bitboard b = blockers & BMask[s];
301 return BAttacks[BAttackIndex[s] +
302 (unsigned(int(b) * int(BMult[s]) ^
303 int(b >> 32) * int(BMult[s] >> 32))
307 #else // defined(USE_32BIT_ATTACKS)
309 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
310 Bitboard b = blockers & BMask[s];
311 return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
314 #endif // defined(USE_32BIT_ATTACKS)
316 inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
317 return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
321 /// squares_between returns a bitboard representing all squares between
322 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
323 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
324 /// on the same line, file or diagonal, EmptyBoardBB is returned.
326 inline Bitboard squares_between(Square s1, Square s2) {
327 return BetweenBB[s1][s2];
331 /// squares_in_front_of takes a color and a square as input, and returns a
332 /// bitboard representing all squares along the line in front of the square,
333 /// from the point of view of the given color. For instance,
334 /// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
335 /// e3, e2 and e1 set.
337 inline Bitboard squares_in_front_of(Color c, Square s) {
338 return in_front_bb(c, s) & file_bb(s);
342 /// squares_behind is similar to squares_in_front, but returns the squares
343 /// behind the square instead of in front of the square.
345 inline Bitboard squares_behind(Color c, Square s) {
346 return in_front_bb(opposite_color(c), s) & file_bb(s);
350 /// passed_pawn_mask takes a color and a square as input, and returns a
351 /// bitboard mask which can be used to test if a pawn of the given color on
352 /// the given square is a passed pawn.
354 inline Bitboard passed_pawn_mask(Color c, Square s) {
355 return PassedPawnMask[c][s];
359 /// outpost_mask takes a color and a square as input, and returns a bitboard
360 /// mask which can be used to test whether a piece on the square can possibly
361 /// be driven away by an enemy pawn.
363 inline Bitboard outpost_mask(Color c, Square s) {
364 return OutpostMask[c][s];
368 /// isolated_pawn_mask takes a square as input, and returns a bitboard mask
369 /// which can be used to test whether a pawn on the given square is isolated.
371 inline Bitboard isolated_pawn_mask(Square s) {
372 return neighboring_files_bb(s);
376 /// count_1s() counts the number of nonzero bits in a bitboard.
378 #if defined(BITCOUNT_LOOP)
380 inline int count_1s(Bitboard b) {
382 for(r = 0; b; r++, b &= b - 1);
386 inline int count_1s_max_15(Bitboard b) {
390 #elif defined(BITCOUNT_SWAR_32)
392 inline int count_1s(Bitboard b) {
393 unsigned w = unsigned(b >> 32), v = unsigned(b);
394 v = v - ((v >> 1) & 0x55555555);
395 w = w - ((w >> 1) & 0x55555555);
396 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
397 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
398 v = (v + (v >> 4)) & 0x0F0F0F0F;
399 w = (w + (w >> 4)) & 0x0F0F0F0F;
400 v = ((v+w) * 0x01010101) >> 24; // mul is fast on amd procs
404 inline int count_1s_max_15(Bitboard b) {
405 unsigned w = unsigned(b >> 32), v = unsigned(b);
406 v = v - ((v >> 1) & 0x55555555);
407 w = w - ((w >> 1) & 0x55555555);
408 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
409 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
410 v = ((v+w) * 0x11111111) >> 28;
414 #elif defined(BITCOUNT_SWAR_64)
416 inline int count_1s(Bitboard b) {
417 b -= ((b>>1) & 0x5555555555555555ULL);
418 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
419 b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
420 b *= 0x0101010101010101ULL;
424 inline int count_1s_max_15(Bitboard b) {
425 b -= (b>>1) & 0x5555555555555555ULL;
426 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
427 b *= 0x1111111111111111ULL;
438 extern void print_bitboard(Bitboard b);
439 extern void init_bitboards();
440 extern Square first_1(Bitboard b);
441 extern Square pop_1st_bit(Bitboard *b);
444 #endif // !defined(BITBOARD_H_INCLUDED)