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 //#define USE_COMPACT_ROOK_ATTACKS
29 //#define USE_32BIT_ATTACKS
30 #define USE_FOLDED_BITSCAN
32 #define BITCOUNT_SWAR_64
33 //#define BITCOUNT_SWAR_32
34 //#define BITCOUNT_LOOP
42 #include "direction.h"
52 typedef uint64_t Bitboard;
56 //// Constants and variables
59 const Bitboard EmptyBoardBB = 0ULL;
61 const Bitboard WhiteSquaresBB = 0x55AA55AA55AA55AAULL;
62 const Bitboard BlackSquaresBB = 0xAA55AA55AA55AA55ULL;
64 extern const Bitboard SquaresByColorBB[2];
66 const Bitboard FileABB = 0x0101010101010101ULL;
67 const Bitboard FileBBB = 0x0202020202020202ULL;
68 const Bitboard FileCBB = 0x0404040404040404ULL;
69 const Bitboard FileDBB = 0x0808080808080808ULL;
70 const Bitboard FileEBB = 0x1010101010101010ULL;
71 const Bitboard FileFBB = 0x2020202020202020ULL;
72 const Bitboard FileGBB = 0x4040404040404040ULL;
73 const Bitboard FileHBB = 0x8080808080808080ULL;
75 extern const Bitboard FileBB[8];
76 extern const Bitboard NeighboringFilesBB[8];
77 extern const Bitboard ThisAndNeighboringFilesBB[8];
79 const Bitboard Rank1BB = 0xFFULL;
80 const Bitboard Rank2BB = 0xFF00ULL;
81 const Bitboard Rank3BB = 0xFF0000ULL;
82 const Bitboard Rank4BB = 0xFF000000ULL;
83 const Bitboard Rank5BB = 0xFF00000000ULL;
84 const Bitboard Rank6BB = 0xFF0000000000ULL;
85 const Bitboard Rank7BB = 0xFF000000000000ULL;
86 const Bitboard Rank8BB = 0xFF00000000000000ULL;
88 extern const Bitboard RankBB[8];
89 extern const Bitboard RelativeRankBB[2][8];
90 extern const Bitboard InFrontBB[2][8];
92 extern Bitboard SetMaskBB[64];
93 extern Bitboard ClearMaskBB[64];
95 extern Bitboard StepAttackBB[16][64];
96 extern Bitboard RayBB[64][8];
97 extern Bitboard BetweenBB[64][64];
99 extern Bitboard PassedPawnMask[2][64];
100 extern Bitboard OutpostMask[2][64];
102 #if defined(USE_COMPACT_ROOK_ATTACKS)
103 extern Bitboard RankAttacks[8][64], FileAttacks[8][64];
105 extern const uint64_t RMult[64];
106 extern const int RShift[64];
107 extern Bitboard RMask[64];
108 extern int RAttackIndex[64];
109 extern Bitboard RAttacks[0x19000];
110 #endif // defined(USE_COMPACT_ROOK_ATTACKS)
112 extern const uint64_t BMult[64];
113 extern const int BShift[64];
114 extern Bitboard BMask[64];
115 extern int BAttackIndex[64];
116 extern Bitboard BAttacks[0x1480];
118 extern Bitboard BishopPseudoAttacks[64];
119 extern Bitboard RookPseudoAttacks[64];
120 extern Bitboard QueenPseudoAttacks[64];
124 //// Inline functions
127 /// Functions for testing whether a given bit is set in a bitboard, and for
128 /// setting and clearing bits.
130 inline Bitboard set_mask_bb(Square s) {
135 inline Bitboard clear_mask_bb(Square s) {
136 // return ~set_mask_bb(s);
137 return ClearMaskBB[s];
140 inline Bitboard bit_is_set(Bitboard b, Square s) {
141 return b & set_mask_bb(s);
144 inline void set_bit(Bitboard *b, Square s) {
145 *b |= set_mask_bb(s);
148 inline void clear_bit(Bitboard *b, Square s) {
149 *b &= clear_mask_bb(s);
153 /// rank_bb() and file_bb() gives a bitboard containing all squares on a given
154 /// file or rank. It is also possible to pass a square as input to these
157 inline Bitboard rank_bb(Rank r) {
161 inline Bitboard rank_bb(Square s) {
162 return rank_bb(square_rank(s));
165 inline Bitboard file_bb(File f) {
169 inline Bitboard file_bb(Square s) {
170 return file_bb(square_file(s));
174 /// neighboring_files_bb takes a file or a square as input, and returns a
175 /// bitboard representing all squares on the neighboring files.
177 inline Bitboard neighboring_files_bb(File f) {
178 return NeighboringFilesBB[f];
181 inline Bitboard neighboring_files_bb(Square s) {
182 return neighboring_files_bb(square_file(s));
186 /// this_and_neighboring_files_bb takes a file or a square as input, and
187 /// returns a bitboard representing all squares on the given and neighboring
190 inline Bitboard this_and_neighboring_files_bb(File f) {
191 return ThisAndNeighboringFilesBB[f];
194 inline Bitboard this_and_neighboring_files_bb(Square s) {
195 return this_and_neighboring_files_bb(square_file(s));
199 /// relative_rank_bb() takes a color and a rank as input, and returns a bitboard
200 /// representing all squares on the given rank from the given color's point of
201 /// view. For instance, relative_rank_bb(WHITE, 7) gives all squares on the
202 /// 7th rank, while relative_rank_bb(BLACK, 7) gives all squares on the 2nd
205 inline Bitboard relative_rank_bb(Color c, Rank r) {
206 return RelativeRankBB[c][r];
210 /// in_front_bb() takes a color and a rank or square as input, and returns a
211 /// bitboard representing all the squares on all ranks in front of the rank
212 /// (or square), from the given color's point of view. For instance,
213 /// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
214 /// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
216 inline Bitboard in_front_bb(Color c, Rank r) {
217 return InFrontBB[c][r];
220 inline Bitboard in_front_bb(Color c, Square s) {
221 return in_front_bb(c, square_rank(s));
225 /// ray_bb() gives a bitboard representing all squares along the ray in a
226 /// given direction from a given square.
228 inline Bitboard ray_bb(Square s, SignedDirection d) {
233 /// Functions for computing sliding attack bitboards. rook_attacks_bb(),
234 /// bishop_attacks_bb() and queen_attacks_bb() all take a square and a
235 /// bitboard of occupied squares as input, and return a bitboard representing
236 /// all squares attacked by a rook, bishop or queen on the given square.
238 #if defined(USE_COMPACT_ROOK_ATTACKS)
240 inline Bitboard file_attacks_bb(Square s, Bitboard blockers) {
241 Bitboard b = (blockers >> square_file(s)) & 0x01010101010100ULL;
243 FileAttacks[square_rank(s)][(b*0xd6e8802041d0c441ULL)>>58] & file_bb(s);
246 inline Bitboard rank_attacks_bb(Square s, Bitboard blockers) {
247 Bitboard b = (blockers >> ((s & 56) + 1)) & 63;
248 return RankAttacks[square_file(s)][b] & rank_bb(s);
251 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
252 return file_attacks_bb(s, blockers) | rank_attacks_bb(s, blockers);
255 #elif defined(USE_32BIT_ATTACKS)
257 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
258 Bitboard b = blockers & RMask[s];
259 return RAttacks[RAttackIndex[s] +
260 (unsigned(int(b) * int(RMult[s]) ^
261 int(b >> 32) * int(RMult[s] >> 32))
267 inline Bitboard rook_attacks_bb(Square s, Bitboard blockers) {
268 Bitboard b = blockers & RMask[s];
269 return RAttacks[RAttackIndex[s] + ((b * RMult[s]) >> RShift[s])];
274 #if defined(USE_32BIT_ATTACKS)
276 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
277 Bitboard b = blockers & BMask[s];
278 return BAttacks[BAttackIndex[s] +
279 (unsigned(int(b) * int(BMult[s]) ^
280 int(b >> 32) * int(BMult[s] >> 32))
284 #else // defined(USE_32BIT_ATTACKS)
286 inline Bitboard bishop_attacks_bb(Square s, Bitboard blockers) {
287 Bitboard b = blockers & BMask[s];
288 return BAttacks[BAttackIndex[s] + ((b * BMult[s]) >> BShift[s])];
291 #endif // defined(USE_32BIT_ATTACKS)
293 inline Bitboard queen_attacks_bb(Square s, Bitboard blockers) {
294 return rook_attacks_bb(s, blockers) | bishop_attacks_bb(s, blockers);
298 /// squares_between returns a bitboard representing all squares between
299 /// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
300 /// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
301 /// on the same line, file or diagonal, EmptyBoardBB is returned.
303 inline Bitboard squares_between(Square s1, Square s2) {
304 return BetweenBB[s1][s2];
308 /// squares_in_front_of takes a color and a square as input, and returns a
309 /// bitboard representing all squares along the line in front of the square,
310 /// from the point of view of the given color. For instance,
311 /// squares_in_front_of(BLACK, SQ_E4) returns a bitboard with the squares
312 /// e3, e2 and e1 set.
314 inline Bitboard squares_in_front_of(Color c, Square s) {
315 return in_front_bb(c, s) & file_bb(s);
319 /// squares_behind is similar to squares_in_front, but returns the squares
320 /// behind the square instead of in front of the square.
322 inline Bitboard squares_behind(Color c, Square s) {
323 return in_front_bb(opposite_color(c), s) & file_bb(s);
327 /// passed_pawn_mask takes a color and a square as input, and returns a
328 /// bitboard mask which can be used to test if a pawn of the given color on
329 /// the given square is a passed pawn.
331 inline Bitboard passed_pawn_mask(Color c, Square s) {
332 return PassedPawnMask[c][s];
336 /// outpost_mask takes a color and a square as input, and returns a bitboard
337 /// mask which can be used to test whether a piece on the square can possibly
338 /// be driven away by an enemy pawn.
340 inline Bitboard outpost_mask(Color c, Square s) {
341 return OutpostMask[c][s];
345 /// isolated_pawn_mask takes a square as input, and returns a bitboard mask
346 /// which can be used to test whether a pawn on the given square is isolated.
348 inline Bitboard isolated_pawn_mask(Square s) {
349 return neighboring_files_bb(s);
353 /// count_1s() counts the number of nonzero bits in a bitboard.
355 #if defined(BITCOUNT_LOOP)
357 inline int count_1s(Bitboard b) {
359 for(r = 0; b; r++, b &= b - 1);
363 inline int count_1s_max_15(Bitboard b) {
367 #elif defined(BITCOUNT_SWAR_32)
369 inline int count_1s(Bitboard b) {
370 unsigned w = unsigned(b >> 32), v = unsigned(b);
371 v = v - ((v >> 1) & 0x55555555);
372 w = w - ((w >> 1) & 0x55555555);
373 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
374 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
375 v = (v + (v >> 4)) & 0x0F0F0F0F;
376 w = (w + (w >> 4)) & 0x0F0F0F0F;
377 v = ((v+w) * 0x01010101) >> 24; // mul is fast on amd procs
381 inline int count_1s_max_15(Bitboard b) {
382 unsigned w = unsigned(b >> 32), v = unsigned(b);
383 v = v - ((v >> 1) & 0x55555555);
384 w = w - ((w >> 1) & 0x55555555);
385 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
386 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
387 v = ((v+w) * 0x11111111) >> 28;
391 #elif defined(BITCOUNT_SWAR_64)
393 inline int count_1s(Bitboard b) {
394 b -= ((b>>1) & 0x5555555555555555ULL);
395 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
396 b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
397 b *= 0x0101010101010101ULL;
401 inline int count_1s_max_15(Bitboard b) {
402 b -= (b>>1) & 0x5555555555555555ULL;
403 b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
404 b *= 0x1111111111111111ULL;
415 extern void print_bitboard(Bitboard b);
416 extern void init_bitboards();
417 extern Square first_1(Bitboard b);
418 extern Square pop_1st_bit(Bitboard *b);
421 #endif // !defined(BITBOARD_H_INCLUDED)