2 Glaurung, a UCI chess playing engine.
3 Copyright (C) 2004-2008 Tord Romstad
5 Glaurung is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 Glaurung is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #if !defined(BITBOARD_H_INCLUDED)
21 #define BITBOARD_H_INCLUDED
28 // Comment following define if you prefer manually adjust
29 // platform macros defined below
30 #define AUTO_CONFIGURATION
33 // Check for 64 bits for different compilers: Intel, MSVC and gcc
34 #if defined(__x86_64) || defined(_WIN64) || (__SIZEOF_INT__ > 4)
38 #if !defined(AUTO_CONFIGURATION) || defined(IS_64BIT)
40 //#define USE_COMPACT_ROOK_ATTACKS
41 //#define USE_32BIT_ATTACKS
42 #define USE_FOLDED_BITSCAN
44 #define BITCOUNT_SWAR_64
45 //#define BITCOUNT_SWAR_32
46 //#define BITCOUNT_LOOP
50 #define USE_32BIT_ATTACKS
51 #define USE_FOLDED_BITSCAN
52 #define BITCOUNT_SWAR_32
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;
82 extern const Bitboard SquaresByColorBB[2];
84 const Bitboard FileABB = 0x0101010101010101ULL;
85 const Bitboard FileBBB = 0x0202020202020202ULL;
86 const Bitboard FileCBB = 0x0404040404040404ULL;
87 const Bitboard FileDBB = 0x0808080808080808ULL;
88 const Bitboard FileEBB = 0x1010101010101010ULL;
89 const Bitboard FileFBB = 0x2020202020202020ULL;
90 const Bitboard FileGBB = 0x4040404040404040ULL;
91 const Bitboard FileHBB = 0x8080808080808080ULL;
93 extern const Bitboard FileBB[8];
94 extern const Bitboard NeighboringFilesBB[8];
95 extern const Bitboard ThisAndNeighboringFilesBB[8];
97 const Bitboard Rank1BB = 0xFFULL;
98 const Bitboard Rank2BB = 0xFF00ULL;
99 const Bitboard Rank3BB = 0xFF0000ULL;
100 const Bitboard Rank4BB = 0xFF000000ULL;
101 const Bitboard Rank5BB = 0xFF00000000ULL;
102 const Bitboard Rank6BB = 0xFF0000000000ULL;
103 const Bitboard Rank7BB = 0xFF000000000000ULL;
104 const Bitboard Rank8BB = 0xFF00000000000000ULL;
106 extern const Bitboard RankBB[8];
107 extern const Bitboard RelativeRankBB[2][8];
108 extern const Bitboard InFrontBB[2][8];
110 extern Bitboard SetMaskBB[64];
111 extern Bitboard ClearMaskBB[64];
113 extern Bitboard StepAttackBB[16][64];
114 extern Bitboard RayBB[64][8];
115 extern Bitboard BetweenBB[64][64];
117 extern Bitboard PassedPawnMask[2][64];
118 extern Bitboard OutpostMask[2][64];
120 #if defined(USE_COMPACT_ROOK_ATTACKS)
121 extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
123 extern const uint64_t RMult[64];
124 extern const int RShift[64];
125 extern Bitboard RMask[64];
126 extern int RAttackIndex[64];
127 extern Bitboard RAttacks[0x19000];
128 #endif // defined(USE_COMPACT_ROOK_ATTACKS)
130 extern const uint64_t BMult[64];
131 extern const int BShift[64];
132 extern Bitboard BMask[64];
133 extern int BAttackIndex[64];
134 extern Bitboard BAttacks[0x1480];
136 extern Bitboard BishopPseudoAttacks[64];
137 extern Bitboard RookPseudoAttacks[64];
138 extern Bitboard QueenPseudoAttacks[64];
142 //// Inline functions
145 /// Functions for testing whether a given bit is set in a bitboard, and for
146 /// setting and clearing bits.
148 inline Bitboard set_mask_bb(Square s) {
153 inline Bitboard clear_mask_bb(Square s) {
154 // return ~set_mask_bb(s);
155 return ClearMaskBB[s];
158 inline Bitboard bit_is_set(Bitboard b, Square s) {
159 return b & set_mask_bb(s);
162 inline void set_bit(Bitboard *b, Square s) {
163 *b |= set_mask_bb(s);
166 inline void clear_bit(Bitboard *b, Square s) {
167 *b &= clear_mask_bb(s);
171 /// rank_bb() and file_bb() gives a bitboard containing all squares on a given
172 /// file or rank. It is also possible to pass a square as input to these
175 inline Bitboard rank_bb(Rank r) {
179 inline Bitboard rank_bb(Square s) {
180 return rank_bb(square_rank(s));
183 inline Bitboard file_bb(File f) {
187 inline Bitboard file_bb(Square s) {
188 return file_bb(square_file(s));
192 /// neighboring_files_bb takes a file or a square as input, and returns a
193 /// bitboard representing all squares on the neighboring files.
195 inline Bitboard neighboring_files_bb(File f) {
196 return NeighboringFilesBB[f];
199 inline Bitboard neighboring_files_bb(Square s) {
200 return neighboring_files_bb(square_file(s));
204 /// this_and_neighboring_files_bb takes a file or a square as input, and
205 /// returns a bitboard representing all squares on the given and neighboring
208 inline Bitboard this_and_neighboring_files_bb(File f) {
209 return ThisAndNeighboringFilesBB[f];
212 inline Bitboard this_and_neighboring_files_bb(Square s) {
213 return this_and_neighboring_files_bb(square_file(s));
217 /// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
218 /// representing all squares on the given rank from the given color's point of
219 /// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
220 /// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
223 inline Bitboard relative_rank_bb(Color c, Rank r) {
224 return RelativeRankBB[c][r];
228 /// in_front_bb() takes a color and a rank or square as input, and returns a
229 /// bitboard representing all the squares on all ranks in front of the rank
230 /// (or square), from the given color's point of view. For instance,
231 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
232 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
234 inline Bitboard in_front_bb(Color c, Rank r) {
235 return InFrontBB[c][r];
238 inline Bitboard in_front_bb(Color c, Square s) {
239 return in_front_bb(c, square_rank(s));
243 /// ray_bb() gives a bitboard representing all squares along the ray in a
244 /// given direction from a given square.
246 inline Bitboard ray_bb(Square s, SignedDirection d) {
251 /// Functions for computing sliding attack bitboards. rook_attacks_bb(),
252 /// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
253 /// bitboard of occupied squares as input, and return a bitboard representing
254 /// all squares attacked by a rook, bishop or queen on the given square.
256 #if defined(USE_COMPACT_ROOK_ATTACKS)
258 inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
259 Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
261 FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
264 inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
265 Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
266 return RankAttacks[square_file(s)][b] & rank_bb(s);
269 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
270 return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
273 #elif defined(USE_32BIT_ATTACKS)
275 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
276 Bitboard b = blockers & RMask[s];
277 return RAttacks[RAttackIndex[s] +
278 (unsigned(int(b) * int(RMult[s]) ^
279 int(b >> 32) * int(RMult[s] >> 32))
285 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
286 Bitboard b = blockers & RMask[s];
287 return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
292 #if defined(USE_32BIT_ATTACKS)
294 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
295 Bitboard b = blockers & BMask[s];
296 return BAttacks[BAttackIndex[s] +
297 (unsigned(int(b) * int(BMult[s]) ^
298 int(b >> 32) * int(BMult[s] >> 32))
302 #else // defined(USE_32BIT_ATTACKS)
304 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
305 Bitboard b = blockers & BMask[s];
306 return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
309 #endif // defined(USE_32BIT_ATTACKS)
311 inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
312 return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
316 /// squares_between returns a bitboard representing all squares between
317 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
318 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
319 /// on the same line, file or diagonal, EmptyBoardBB is returned.
321 inline Bitboard squares_between(Square s1, Square s2) {
322 return BetweenBB[s1][s2];
326 /// squares_in_front_of takes a color and a square as input, and returns a
327 /// bitboard representing all squares along the line in front of the square,
328 /// from the point of view of the given color. For instance,
329 /// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
330 /// e3, e2 and e1 set.
332 inline Bitboard squares_in_front_of(Color c, Square s) {
333 return in_front_bb(c, s) & file_bb(s);
337 /// squares_behind is similar to squares_in_front, but returns the squares
338 /// behind the square instead of in front of the square.
340 inline Bitboard squares_behind(Color c, Square s) {
341 return in_front_bb(opposite_color(c), s) & file_bb(s);
345 /// passed_pawn_mask takes a color and a square as input, and returns a
346 /// bitboard mask which can be used to test if a pawn of the given color on
347 /// the given square is a passed pawn.
349 inline Bitboard passed_pawn_mask(Color c, Square s) {
350 return PassedPawnMask[c][s];
354 /// outpost_mask takes a color and a square as input, and returns a bitboard
355 /// mask which can be used to test whether a piece on the square can possibly
356 /// be driven away by an enemy pawn.
358 inline Bitboard outpost_mask(Color c, Square s) {
359 return OutpostMask[c][s];
363 /// isolated_pawn_mask takes a square as input, and returns a bitboard mask
364 /// which can be used to test whether a pawn on the given square is isolated.
366 inline Bitboard isolated_pawn_mask(Square s) {
367 return neighboring_files_bb(s);
371 /// count_1s() counts the number of nonzero bits in a bitboard.
373 #if defined(BITCOUNT_LOOP)
375 inline int count_1s(Bitboard b) {
377 for(r = 0; b; r++, b &= b - 1);
381 inline int count_1s_max_15(Bitboard b) {
385 #elif defined(BITCOUNT_SWAR_32)
387 inline int count_1s(Bitboard b) {
388 unsigned w = unsigned(b >> 32), v = unsigned(b);
389 v = v - ((v >> 1) & 0x55555555);
390 w = w - ((w >> 1) & 0x55555555);
391 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
392 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
393 v = (v + (v >> 4)) & 0x0F0F0F0F;
394 w = (w + (w >> 4)) & 0x0F0F0F0F;
395 v = ((v+w) * 0x01010101) >> 24; // mul is fast on amd procs
399 inline int count_1s_max_15(Bitboard b) {
400 unsigned w = unsigned(b >> 32), v = unsigned(b);
401 v = v - ((v >> 1) & 0x55555555);
402 w = w - ((w >> 1) & 0x55555555);
403 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
404 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
405 v = ((v+w) * 0x11111111) >> 28;
409 #elif defined(BITCOUNT_SWAR_64)
411 inline int count_1s(Bitboard b) {
412 b -= ((b>>1) & 0x5555555555555555ULL);
413 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
414 b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
415 b *= 0x0101010101010101ULL;
419 inline int count_1s_max_15(Bitboard b) {
420 b -= (b>>1) & 0x5555555555555555ULL;
421 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
422 b *= 0x1111111111111111ULL;
433 extern void print_bitboard(Bitboard b);
434 extern void init_bitboards();
435 extern Square first_1(Bitboard b);
436 extern Square pop_1st_bit(Bitboard *b);
439 #endif // !defined(BITBOARD_H_INCLUDED)