2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
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/>.
33 const uint64_t BMult[64] = {
34 0x440049104032280ULL, 0x1021023c82008040ULL, 0x404040082000048ULL,
35 0x48c4440084048090ULL, 0x2801104026490000ULL, 0x4100880442040800ULL,
36 0x181011002e06040ULL, 0x9101004104200e00ULL, 0x1240848848310401ULL,
37 0x2000142828050024ULL, 0x1004024d5000ULL, 0x102044400800200ULL,
38 0x8108108820112000ULL, 0xa880818210c00046ULL, 0x4008008801082000ULL,
39 0x60882404049400ULL, 0x104402004240810ULL, 0xa002084250200ULL,
40 0x100b0880801100ULL, 0x4080201220101ULL, 0x44008080a00000ULL,
41 0x202200842000ULL, 0x5006004882d00808ULL, 0x200045080802ULL,
42 0x86100020200601ULL, 0xa802080a20112c02ULL, 0x80411218080900ULL,
43 0x200a0880080a0ULL, 0x9a01010000104000ULL, 0x28008003100080ULL,
44 0x211021004480417ULL, 0x401004188220806ULL, 0x825051400c2006ULL,
45 0x140c0210943000ULL, 0x242800300080ULL, 0xc2208120080200ULL,
46 0x2430008200002200ULL, 0x1010100112008040ULL, 0x8141050100020842ULL,
47 0x822081014405ULL, 0x800c049e40400804ULL, 0x4a0404028a000820ULL,
48 0x22060201041200ULL, 0x360904200840801ULL, 0x881a08208800400ULL,
49 0x60202c00400420ULL, 0x1204440086061400ULL, 0x8184042804040ULL,
50 0x64040315300400ULL, 0xc01008801090a00ULL, 0x808010401140c00ULL,
51 0x4004830c2020040ULL, 0x80005002020054ULL, 0x40000c14481a0490ULL,
52 0x10500101042048ULL, 0x1010100200424000ULL, 0x640901901040ULL,
53 0xa0201014840ULL, 0x840082aa011002ULL, 0x10010840084240aULL,
54 0x420400810420608ULL, 0x8d40230408102100ULL, 0x4a00200612222409ULL,
58 const uint64_t RMult[64] = {
59 0xa8002c000108020ULL, 0x4440200140003000ULL, 0x8080200010011880ULL,
60 0x380180080141000ULL, 0x1a00060008211044ULL, 0x410001000a0c0008ULL,
61 0x9500060004008100ULL, 0x100024284a20700ULL, 0x802140008000ULL,
62 0x80c01002a00840ULL, 0x402004282011020ULL, 0x9862000820420050ULL,
63 0x1001448011100ULL, 0x6432800200800400ULL, 0x40100010002000cULL,
64 0x2800d0010c080ULL, 0x90c0008000803042ULL, 0x4010004000200041ULL,
65 0x3010010200040ULL, 0xa40828028001000ULL, 0x123010008000430ULL,
66 0x24008004020080ULL, 0x60040001104802ULL, 0x582200028400d1ULL,
67 0x4000802080044000ULL, 0x408208200420308ULL, 0x610038080102000ULL,
68 0x3601000900100020ULL, 0x80080040180ULL, 0xc2020080040080ULL,
69 0x80084400100102ULL, 0x4022408200014401ULL, 0x40052040800082ULL,
70 0xb08200280804000ULL, 0x8a80a008801000ULL, 0x4000480080801000ULL,
71 0x911808800801401ULL, 0x822a003002001894ULL, 0x401068091400108aULL,
72 0x4a10a00004cULL, 0x2000800640008024ULL, 0x1486408102020020ULL,
73 0x100a000d50041ULL, 0x810050020b0020ULL, 0x204000800808004ULL,
74 0x20048100a000cULL, 0x112000831020004ULL, 0x9000040810002ULL,
75 0x440490200208200ULL, 0x8910401000200040ULL, 0x6404200050008480ULL,
76 0x4b824a2010010100ULL, 0x4080801810c0080ULL, 0x400802a0080ULL,
77 0x8224080110026400ULL, 0x40002c4104088200ULL, 0x1002100104a0282ULL,
78 0x1208400811048021ULL, 0x3201014a40d02001ULL, 0x5100019200501ULL,
79 0x101000208001005ULL, 0x2008450080702ULL, 0x1002080301d00cULL,
83 const int BShift[64] = {
84 58, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 59, 59,
85 59, 59, 57, 57, 57, 57, 59, 59, 59, 59, 57, 55, 55, 57, 59, 59,
86 59, 59, 57, 55, 55, 57, 59, 59, 59, 59, 57, 57, 57, 57, 59, 59,
87 59, 59, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 58
90 const int RShift[64] = {
91 52, 53, 53, 53, 53, 53, 53, 52, 53, 54, 54, 54, 54, 54, 54, 53,
92 53, 54, 54, 54, 54, 54, 54, 53, 53, 54, 54, 54, 54, 54, 54, 53,
93 53, 54, 54, 54, 54, 54, 54, 53, 53, 54, 54, 54, 54, 54, 54, 53,
94 53, 54, 54, 54, 54, 54, 54, 53, 52, 53, 53, 53, 53, 53, 53, 52
97 #else // if !defined(IS_64BIT)
99 const uint64_t BMult[64] = {
100 0x54142844c6a22981ULL, 0x710358a6ea25c19eULL, 0x704f746d63a4a8dcULL,
101 0xbfed1a0b80f838c5ULL, 0x90561d5631e62110ULL, 0x2804260376e60944ULL,
102 0x84a656409aa76871ULL, 0xf0267f64c28b6197ULL, 0x70764ebb762f0585ULL,
103 0x92aa09e0cfe161deULL, 0x41ee1f6bb266f60eULL, 0xddcbf04f6039c444ULL,
104 0x5a3fab7bac0d988aULL, 0xd3727877fa4eaa03ULL, 0xd988402d868ddaaeULL,
105 0x812b291afa075c7cULL, 0x94faf987b685a932ULL, 0x3ed867d8470d08dbULL,
106 0x92517660b8901de8ULL, 0x2d97e43e058814b4ULL, 0x880a10c220b25582ULL,
107 0xc7c6520d1f1a0477ULL, 0xdbfc7fbcd7656aa6ULL, 0x78b1b9bfb1a2b84fULL,
108 0x2f20037f112a0bc1ULL, 0x657171ea2269a916ULL, 0xc08302b07142210eULL,
109 0x880a4403064080bULL, 0x3602420842208c00ULL, 0x852800dc7e0b6602ULL,
110 0x595a3fbbaa0f03b2ULL, 0x9f01411558159d5eULL, 0x2b4a4a5f88b394f2ULL,
111 0x4afcbffc292dd03aULL, 0x4a4094a3b3f10522ULL, 0xb06f00b491f30048ULL,
112 0xd5b3820280d77004ULL, 0x8b2e01e7c8e57a75ULL, 0x2d342794e886c2e6ULL,
113 0xc302c410cde21461ULL, 0x111f426f1379c274ULL, 0xe0569220abb31588ULL,
114 0x5026d3064d453324ULL, 0xe2076040c343cd8aULL, 0x93efd1e1738021eeULL,
115 0xb680804bed143132ULL, 0x44e361b21986944cULL, 0x44c60170ef5c598cULL,
116 0xf4da475c195c9c94ULL, 0xa3afbb5f72060b1dULL, 0xbc75f410e41c4ffcULL,
117 0xb51c099390520922ULL, 0x902c011f8f8ec368ULL, 0x950b56b3d6f5490aULL,
118 0x3909e0635bf202d0ULL, 0x5744f90206ec10ccULL, 0xdc59fd76317abbc1ULL,
119 0x881c7c67fcbfc4f6ULL, 0x47ca41e7e440d423ULL, 0xeb0c88112048d004ULL,
120 0x51c60e04359aef1aULL, 0x1aa1fe0e957a5554ULL, 0xdd9448db4f5e3104ULL,
121 0xdc01f6dca4bebbdcULL,
124 const uint64_t RMult[64] = {
125 0xd7445cdec88002c0ULL, 0xd0a505c1f2001722ULL, 0xe065d1c896002182ULL,
126 0x9a8c41e75a000892ULL, 0x8900b10c89002aa8ULL, 0x9b28d1c1d60005a2ULL,
127 0x15d6c88de002d9aULL, 0xb1dbfc802e8016a9ULL, 0x149a1042d9d60029ULL,
128 0xb9c08050599e002fULL, 0x132208c3af300403ULL, 0xc1000ce2e9c50070ULL,
129 0x9d9aa13c99020012ULL, 0xb6b078daf71e0046ULL, 0x9d880182fb6e002eULL,
130 0x52889f467e850037ULL, 0xda6dc008d19a8480ULL, 0x468286034f902420ULL,
131 0x7140ac09dc54c020ULL, 0xd76ffffa39548808ULL, 0xea901c4141500808ULL,
132 0xc91004093f953a02ULL, 0x2882afa8f6bb402ULL, 0xaebe335692442c01ULL,
133 0xe904a22079fb91eULL, 0x13a514851055f606ULL, 0x76c782018c8fe632ULL,
134 0x1dc012a9d116da06ULL, 0x3c9e0037264fffa6ULL, 0x2036002853c6e4a2ULL,
135 0xe3fe08500afb47d4ULL, 0xf38af25c86b025c2ULL, 0xc0800e2182cf9a40ULL,
136 0x72002480d1f60673ULL, 0x2500200bae6e9b53ULL, 0xc60018c1eefca252ULL,
137 0x600590473e3608aULL, 0x46002c4ab3fe51b2ULL, 0xa200011486bcc8d2ULL,
138 0xb680078095784c63ULL, 0x2742002639bf11aeULL, 0xc7d60021a5bdb142ULL,
139 0xc8c04016bb83d820ULL, 0xbd520028123b4842ULL, 0x9d1600344ac2a832ULL,
140 0x6a808005631c8a05ULL, 0x604600a148d5389aULL, 0xe2e40103d40dea65ULL,
141 0x945b5a0087c62a81ULL, 0x12dc200cd82d28eULL, 0x2431c600b5f9ef76ULL,
142 0xfb142a006a9b314aULL, 0x6870e00a1c97d62ULL, 0x2a9db2004a2689a2ULL,
143 0xd3594600caf5d1a2ULL, 0xee0e4900439344a7ULL, 0x89c4d266ca25007aULL,
144 0x3e0013a2743f97e3ULL, 0x180e31a0431378aULL, 0x3a9e465a4d42a512ULL,
145 0x98d0a11a0c0d9cc2ULL, 0x8e711c1aba19b01eULL, 0x8dcdc836dd201142ULL,
146 0x5ac08a4735370479ULL,
149 const int BShift[64] = {
150 26, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 27, 27,
151 27, 27, 25, 25, 25, 25, 27, 27, 27, 27, 25, 23, 23, 25, 27, 27,
152 27, 27, 25, 23, 23, 25, 27, 27, 27, 27, 25, 25, 25, 25, 27, 27,
153 27, 27, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 26
156 const int RShift[64] = {
157 20, 21, 21, 21, 21, 21, 21, 20, 21, 22, 22, 22, 22, 22, 22, 21,
158 21, 22, 22, 22, 22, 22, 22, 21, 21, 22, 22, 22, 22, 22, 22, 21,
159 21, 22, 22, 22, 22, 22, 22, 21, 21, 22, 22, 22, 22, 22, 22, 21,
160 21, 22, 22, 22, 22, 22, 22, 21, 20, 21, 21, 21, 21, 21, 21, 20
163 #endif // defined(IS_64BIT)
165 const Bitboard LightSquaresBB = 0x55AA55AA55AA55AAULL;
166 const Bitboard DarkSquaresBB = 0xAA55AA55AA55AA55ULL;
168 const Bitboard SquaresByColorBB[2] = { DarkSquaresBB, LightSquaresBB };
170 const Bitboard FileBB[8] = {
171 FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB
174 const Bitboard NeighboringFilesBB[8] = {
175 FileBBB, FileABB|FileCBB, FileBBB|FileDBB, FileCBB|FileEBB,
176 FileDBB|FileFBB, FileEBB|FileGBB, FileFBB|FileHBB, FileGBB
179 const Bitboard ThisAndNeighboringFilesBB[8] = {
180 FileABB|FileBBB, FileABB|FileBBB|FileCBB,
181 FileBBB|FileCBB|FileDBB, FileCBB|FileDBB|FileEBB,
182 FileDBB|FileEBB|FileFBB, FileEBB|FileFBB|FileGBB,
183 FileFBB|FileGBB|FileHBB, FileGBB|FileHBB
186 const Bitboard RankBB[8] = {
187 Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB
190 const Bitboard RelativeRankBB[2][8] = {
191 { Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB },
192 { Rank8BB, Rank7BB, Rank6BB, Rank5BB, Rank4BB, Rank3BB, Rank2BB, Rank1BB }
195 const Bitboard InFrontBB[2][8] = {
196 { Rank2BB | Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
197 Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
198 Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
199 Rank5BB | Rank6BB | Rank7BB | Rank8BB,
200 Rank6BB | Rank7BB | Rank8BB,
208 Rank3BB | Rank2BB | Rank1BB,
209 Rank4BB | Rank3BB | Rank2BB | Rank1BB,
210 Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
211 Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
212 Rank7BB | Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB
217 int RAttackIndex[64];
218 Bitboard RAttacks[0x19000];
221 int BAttackIndex[64];
222 Bitboard BAttacks[0x1480];
224 Bitboard SetMaskBB[65];
225 Bitboard ClearMaskBB[65];
227 Bitboard StepAttackBB[16][64];
228 Bitboard BetweenBB[64][64];
230 Bitboard SquaresInFrontMask[2][64];
231 Bitboard PassedPawnMask[2][64];
232 Bitboard AttackSpanMask[2][64];
234 Bitboard BishopPseudoAttacks[64];
235 Bitboard RookPseudoAttacks[64];
236 Bitboard QueenPseudoAttacks[64];
238 uint8_t BitCount8Bit[256];
242 //// Local definitions
249 void init_between_bitboards();
250 void init_pseudo_attacks();
251 SquareDelta squares_delta(Square orig, Square dest);
252 Bitboard index_to_bitboard(int index, Bitboard mask);
253 Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2],
254 int fmin, int fmax, int rmin, int rmax);
255 void init_sliding_attacks(Bitboard attacks[], int attackIndex[], Bitboard mask[],
256 const int shift[], const Bitboard mult[], int deltas[][2]);
264 /// print_bitboard() prints a bitboard in an easily readable format to the
265 /// standard output. This is sometimes useful for debugging.
267 void print_bitboard(Bitboard b) {
269 for (Rank r = RANK_8; r >= RANK_1; r--)
271 std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
272 for (File f = FILE_A; f <= FILE_H; f++)
273 std::cout << "| " << (bit_is_set(b, make_square(f, r))? 'X' : ' ') << ' ';
275 std::cout << "|" << std::endl;
277 std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
281 /// init_bitboards() initializes various bitboard arrays. It is called during
282 /// program initialization.
284 void init_bitboards() {
286 int rookDeltas[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};
287 int bishopDeltas[4][2] = {{1,1},{-1,1},{1,-1},{-1,-1}};
291 init_between_bitboards();
292 init_sliding_attacks(RAttacks, RAttackIndex, RMask, RShift, RMult, rookDeltas);
293 init_sliding_attacks(BAttacks, BAttackIndex, BMask, BShift, BMult, bishopDeltas);
294 init_pseudo_attacks();
298 /// first_1() finds the least significant nonzero bit in a nonzero bitboard.
299 /// pop_1st_bit() finds and clears the least significant nonzero bit in a
300 /// nonzero bitboard.
302 #if defined(IS_64BIT) && !defined(USE_BSFQ)
304 static CACHE_LINE_ALIGNMENT
305 const int BitTable[64] = {
306 0, 1, 2, 7, 3, 13, 8, 19, 4, 25, 14, 28, 9, 34, 20, 40, 5, 17, 26, 38, 15,
307 46, 29, 48, 10, 31, 35, 54, 21, 50, 41, 57, 63, 6, 12, 18, 24, 27, 33, 39,
308 16, 37, 45, 47, 30, 53, 49, 56, 62, 11, 23, 32, 36, 44, 52, 55, 61, 22, 43,
312 Square first_1(Bitboard b) {
313 return Square(BitTable[((b & -b) * 0x218a392cd3d5dbfULL) >> 58]);
316 Square pop_1st_bit(Bitboard* b) {
319 return Square(BitTable[((bb & -bb) * 0x218a392cd3d5dbfULL) >> 58]);
322 #elif !defined(USE_BSFQ)
324 static CACHE_LINE_ALIGNMENT
325 const int BitTable[64] = {
326 63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2,
327 51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, 52,
328 26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, 28,
329 58, 20, 37, 17, 36, 8
332 Square first_1(Bitboard b) {
335 uint32_t fold = int(b) ^ int(b >> 32);
336 return Square(BitTable[(fold * 0x783a9b23) >> 26]);
344 #if defined (BIGENDIAN)
354 Square pop_1st_bit(Bitboard* bb) {
363 ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
364 u.dw.l &= (u.dw.l - 1);
368 ret = Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
369 u.dw.h &= (u.dw.h - 1);
379 // All functions below are used to precompute various bitboards during
380 // program initialization. Some of the functions may be difficult to
381 // understand, but they all seem to work correctly, and it should never
382 // be necessary to touch any of them.
386 SetMaskBB[SQ_NONE] = 0ULL;
387 ClearMaskBB[SQ_NONE] = ~SetMaskBB[SQ_NONE];
389 for (Square s = SQ_A1; s <= SQ_H8; s++)
391 SetMaskBB[s] = (1ULL << s);
392 ClearMaskBB[s] = ~SetMaskBB[s];
395 for (Color c = WHITE; c <= BLACK; c++)
396 for (Square s = SQ_A1; s <= SQ_H8; s++)
398 SquaresInFrontMask[c][s] = in_front_bb(c, s) & file_bb(s);
399 PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_neighboring_files_bb(s);
400 AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
403 for (Bitboard b = 0; b < 256; b++)
404 BitCount8Bit[b] = (uint8_t)count_1s<CNT32>(b);
407 void init_attacks() {
409 const int step[16][8] = {
411 {7,9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0},
412 {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8}, {0}, {0},
413 {-7,-9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0},
414 {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8}
417 for (int i = 0; i < 64; i++)
418 for (int j = 0; j <= int(BK); j++)
420 StepAttackBB[j][i] = EmptyBoardBB;
421 for (int k = 0; k < 8 && step[j][k] != 0; k++)
423 int l = i + step[j][k];
424 if (l >= 0 && l < 64 && abs((i & 7) - (l & 7)) < 3)
425 StepAttackBB[j][i] |= (1ULL << l);
430 Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2],
431 int fmin=0, int fmax=7, int rmin=0, int rmax=7) {
432 Bitboard result = 0ULL;
436 for (int i = 0; i < dirs; i++)
438 int dx = deltas[i][0];
439 int dy = deltas[i][1];
443 while ( (dx == 0 || (f >= fmin && f <= fmax))
444 && (dy == 0 || (r >= rmin && r <= rmax)))
446 result |= (1ULL << (f + r*8));
447 if (block & (1ULL << (f + r*8)))
457 SquareDelta squares_delta(Square orig, Square dest) {
459 const SquareDelta deltas[] = { DELTA_N, DELTA_NE, DELTA_E, DELTA_SE,
460 DELTA_S, DELTA_SW, DELTA_W, DELTA_NW };
462 for (int idx = 0; idx < 8; idx++)
464 Square s = orig + deltas[idx];
466 while (square_is_ok(s) && square_distance(s, s - deltas[idx]) == 1)
477 void init_between_bitboards() {
482 for (s1 = SQ_A1; s1 <= SQ_H8; s1++)
483 for (s2 = SQ_A1; s2 <= SQ_H8; s2++)
485 BetweenBB[s1][s2] = EmptyBoardBB;
486 d = squares_delta(s1, s2);
489 for (s3 = s1 + d; s3 != s2; s3 += d)
490 set_bit(&(BetweenBB[s1][s2]), s3);
494 Bitboard index_to_bitboard(int index, Bitboard mask) {
496 Bitboard result = 0ULL;
497 int bits = count_1s<CNT32>(mask);
499 for (int i = 0; i < bits; i++)
501 int j = pop_1st_bit(&mask);
502 if (index & (1 << i))
503 result |= (1ULL << j);
508 void init_sliding_attacks(Bitboard attacks[], int attackIndex[], Bitboard mask[],
509 const int shift[], const Bitboard mult[], int deltas[][2]) {
511 for (int i = 0, index = 0; i < 64; i++)
513 attackIndex[i] = index;
514 mask[i] = sliding_attacks(i, 0, 4, deltas, 1, 6, 1, 6);
516 #if defined(IS_64BIT)
517 int j = (1 << (64 - shift[i]));
519 int j = (1 << (32 - shift[i]));
522 for (int k = 0; k < j; k++)
524 #if defined(IS_64BIT)
525 Bitboard b = index_to_bitboard(k, mask[i]);
526 attacks[index + ((b * mult[i]) >> shift[i])] = sliding_attacks(i, b, 4, deltas);
528 Bitboard b = index_to_bitboard(k, mask[i]);
529 unsigned v = int(b) * int(mult[i]) ^ int(b >> 32) * int(mult[i] >> 32);
530 attacks[index + (v >> shift[i])] = sliding_attacks(i, b, 4, deltas);
537 void init_pseudo_attacks() {
539 for (Square s = SQ_A1; s <= SQ_H8; s++)
541 BishopPseudoAttacks[s] = bishop_attacks_bb(s, EmptyBoardBB);
542 RookPseudoAttacks[s] = rook_attacks_bb(s, EmptyBoardBB);
543 QueenPseudoAttacks[s] = queen_attacks_bb(s, EmptyBoardBB);