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.
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/>.
29 #include "direction.h"
34 const uint64_t BMult[64] = {
35 0x440049104032280ULL, 0x1021023c82008040ULL, 0x404040082000048ULL,
36 0x48c4440084048090ULL, 0x2801104026490000ULL, 0x4100880442040800ULL,
37 0x181011002e06040ULL, 0x9101004104200e00ULL, 0x1240848848310401ULL,
38 0x2000142828050024ULL, 0x1004024d5000ULL, 0x102044400800200ULL,
39 0x8108108820112000ULL, 0xa880818210c00046ULL, 0x4008008801082000ULL,
40 0x60882404049400ULL, 0x104402004240810ULL, 0xa002084250200ULL,
41 0x100b0880801100ULL, 0x4080201220101ULL, 0x44008080a00000ULL,
42 0x202200842000ULL, 0x5006004882d00808ULL, 0x200045080802ULL,
43 0x86100020200601ULL, 0xa802080a20112c02ULL, 0x80411218080900ULL,
44 0x200a0880080a0ULL, 0x9a01010000104000ULL, 0x28008003100080ULL,
45 0x211021004480417ULL, 0x401004188220806ULL, 0x825051400c2006ULL,
46 0x140c0210943000ULL, 0x242800300080ULL, 0xc2208120080200ULL,
47 0x2430008200002200ULL, 0x1010100112008040ULL, 0x8141050100020842ULL,
48 0x822081014405ULL, 0x800c049e40400804ULL, 0x4a0404028a000820ULL,
49 0x22060201041200ULL, 0x360904200840801ULL, 0x881a08208800400ULL,
50 0x60202c00400420ULL, 0x1204440086061400ULL, 0x8184042804040ULL,
51 0x64040315300400ULL, 0xc01008801090a00ULL, 0x808010401140c00ULL,
52 0x4004830c2020040ULL, 0x80005002020054ULL, 0x40000c14481a0490ULL,
53 0x10500101042048ULL, 0x1010100200424000ULL, 0x640901901040ULL,
54 0xa0201014840ULL, 0x840082aa011002ULL, 0x10010840084240aULL,
55 0x420400810420608ULL, 0x8d40230408102100ULL, 0x4a00200612222409ULL,
59 const uint64_t RMult[64] = {
60 0xa8002c000108020ULL, 0x4440200140003000ULL, 0x8080200010011880ULL,
61 0x380180080141000ULL, 0x1a00060008211044ULL, 0x410001000a0c0008ULL,
62 0x9500060004008100ULL, 0x100024284a20700ULL, 0x802140008000ULL,
63 0x80c01002a00840ULL, 0x402004282011020ULL, 0x9862000820420050ULL,
64 0x1001448011100ULL, 0x6432800200800400ULL, 0x40100010002000cULL,
65 0x2800d0010c080ULL, 0x90c0008000803042ULL, 0x4010004000200041ULL,
66 0x3010010200040ULL, 0xa40828028001000ULL, 0x123010008000430ULL,
67 0x24008004020080ULL, 0x60040001104802ULL, 0x582200028400d1ULL,
68 0x4000802080044000ULL, 0x408208200420308ULL, 0x610038080102000ULL,
69 0x3601000900100020ULL, 0x80080040180ULL, 0xc2020080040080ULL,
70 0x80084400100102ULL, 0x4022408200014401ULL, 0x40052040800082ULL,
71 0xb08200280804000ULL, 0x8a80a008801000ULL, 0x4000480080801000ULL,
72 0x911808800801401ULL, 0x822a003002001894ULL, 0x401068091400108aULL,
73 0x4a10a00004cULL, 0x2000800640008024ULL, 0x1486408102020020ULL,
74 0x100a000d50041ULL, 0x810050020b0020ULL, 0x204000800808004ULL,
75 0x20048100a000cULL, 0x112000831020004ULL, 0x9000040810002ULL,
76 0x440490200208200ULL, 0x8910401000200040ULL, 0x6404200050008480ULL,
77 0x4b824a2010010100ULL, 0x4080801810c0080ULL, 0x400802a0080ULL,
78 0x8224080110026400ULL, 0x40002c4104088200ULL, 0x1002100104a0282ULL,
79 0x1208400811048021ULL, 0x3201014a40d02001ULL, 0x5100019200501ULL,
80 0x101000208001005ULL, 0x2008450080702ULL, 0x1002080301d00cULL,
84 const int BShift[64] = {
85 58, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 59, 59,
86 59, 59, 57, 57, 57, 57, 59, 59, 59, 59, 57, 55, 55, 57, 59, 59,
87 59, 59, 57, 55, 55, 57, 59, 59, 59, 59, 57, 57, 57, 57, 59, 59,
88 59, 59, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 58
91 const int RShift[64] = {
92 52, 53, 53, 53, 53, 53, 53, 52, 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, 53, 54, 54, 54, 54, 54, 54, 53,
95 53, 54, 54, 54, 54, 54, 54, 53, 52, 53, 53, 53, 53, 53, 53, 52
98 #else // if !defined(IS_64BIT)
100 const uint64_t BMult[64] = {
101 0x54142844c6a22981ULL, 0x710358a6ea25c19eULL, 0x704f746d63a4a8dcULL,
102 0xbfed1a0b80f838c5ULL, 0x90561d5631e62110ULL, 0x2804260376e60944ULL,
103 0x84a656409aa76871ULL, 0xf0267f64c28b6197ULL, 0x70764ebb762f0585ULL,
104 0x92aa09e0cfe161deULL, 0x41ee1f6bb266f60eULL, 0xddcbf04f6039c444ULL,
105 0x5a3fab7bac0d988aULL, 0xd3727877fa4eaa03ULL, 0xd988402d868ddaaeULL,
106 0x812b291afa075c7cULL, 0x94faf987b685a932ULL, 0x3ed867d8470d08dbULL,
107 0x92517660b8901de8ULL, 0x2d97e43e058814b4ULL, 0x880a10c220b25582ULL,
108 0xc7c6520d1f1a0477ULL, 0xdbfc7fbcd7656aa6ULL, 0x78b1b9bfb1a2b84fULL,
109 0x2f20037f112a0bc1ULL, 0x657171ea2269a916ULL, 0xc08302b07142210eULL,
110 0x880a4403064080bULL, 0x3602420842208c00ULL, 0x852800dc7e0b6602ULL,
111 0x595a3fbbaa0f03b2ULL, 0x9f01411558159d5eULL, 0x2b4a4a5f88b394f2ULL,
112 0x4afcbffc292dd03aULL, 0x4a4094a3b3f10522ULL, 0xb06f00b491f30048ULL,
113 0xd5b3820280d77004ULL, 0x8b2e01e7c8e57a75ULL, 0x2d342794e886c2e6ULL,
114 0xc302c410cde21461ULL, 0x111f426f1379c274ULL, 0xe0569220abb31588ULL,
115 0x5026d3064d453324ULL, 0xe2076040c343cd8aULL, 0x93efd1e1738021eeULL,
116 0xb680804bed143132ULL, 0x44e361b21986944cULL, 0x44c60170ef5c598cULL,
117 0xf4da475c195c9c94ULL, 0xa3afbb5f72060b1dULL, 0xbc75f410e41c4ffcULL,
118 0xb51c099390520922ULL, 0x902c011f8f8ec368ULL, 0x950b56b3d6f5490aULL,
119 0x3909e0635bf202d0ULL, 0x5744f90206ec10ccULL, 0xdc59fd76317abbc1ULL,
120 0x881c7c67fcbfc4f6ULL, 0x47ca41e7e440d423ULL, 0xeb0c88112048d004ULL,
121 0x51c60e04359aef1aULL, 0x1aa1fe0e957a5554ULL, 0xdd9448db4f5e3104ULL,
122 0xdc01f6dca4bebbdcULL,
125 const uint64_t RMult[64] = {
126 0xd7445cdec88002c0ULL, 0xd0a505c1f2001722ULL, 0xe065d1c896002182ULL,
127 0x9a8c41e75a000892ULL, 0x8900b10c89002aa8ULL, 0x9b28d1c1d60005a2ULL,
128 0x15d6c88de002d9aULL, 0xb1dbfc802e8016a9ULL, 0x149a1042d9d60029ULL,
129 0xb9c08050599e002fULL, 0x132208c3af300403ULL, 0xc1000ce2e9c50070ULL,
130 0x9d9aa13c99020012ULL, 0xb6b078daf71e0046ULL, 0x9d880182fb6e002eULL,
131 0x52889f467e850037ULL, 0xda6dc008d19a8480ULL, 0x468286034f902420ULL,
132 0x7140ac09dc54c020ULL, 0xd76ffffa39548808ULL, 0xea901c4141500808ULL,
133 0xc91004093f953a02ULL, 0x2882afa8f6bb402ULL, 0xaebe335692442c01ULL,
134 0xe904a22079fb91eULL, 0x13a514851055f606ULL, 0x76c782018c8fe632ULL,
135 0x1dc012a9d116da06ULL, 0x3c9e0037264fffa6ULL, 0x2036002853c6e4a2ULL,
136 0xe3fe08500afb47d4ULL, 0xf38af25c86b025c2ULL, 0xc0800e2182cf9a40ULL,
137 0x72002480d1f60673ULL, 0x2500200bae6e9b53ULL, 0xc60018c1eefca252ULL,
138 0x600590473e3608aULL, 0x46002c4ab3fe51b2ULL, 0xa200011486bcc8d2ULL,
139 0xb680078095784c63ULL, 0x2742002639bf11aeULL, 0xc7d60021a5bdb142ULL,
140 0xc8c04016bb83d820ULL, 0xbd520028123b4842ULL, 0x9d1600344ac2a832ULL,
141 0x6a808005631c8a05ULL, 0x604600a148d5389aULL, 0xe2e40103d40dea65ULL,
142 0x945b5a0087c62a81ULL, 0x12dc200cd82d28eULL, 0x2431c600b5f9ef76ULL,
143 0xfb142a006a9b314aULL, 0x6870e00a1c97d62ULL, 0x2a9db2004a2689a2ULL,
144 0xd3594600caf5d1a2ULL, 0xee0e4900439344a7ULL, 0x89c4d266ca25007aULL,
145 0x3e0013a2743f97e3ULL, 0x180e31a0431378aULL, 0x3a9e465a4d42a512ULL,
146 0x98d0a11a0c0d9cc2ULL, 0x8e711c1aba19b01eULL, 0x8dcdc836dd201142ULL,
147 0x5ac08a4735370479ULL,
150 const int BShift[64] = {
151 26, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 27, 27,
152 27, 27, 25, 25, 25, 25, 27, 27, 27, 27, 25, 23, 23, 25, 27, 27,
153 27, 27, 25, 23, 23, 25, 27, 27, 27, 27, 25, 25, 25, 25, 27, 27,
154 27, 27, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 26
157 const int RShift[64] = {
158 20, 21, 21, 21, 21, 21, 21, 20, 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, 21, 22, 22, 22, 22, 22, 22, 21,
161 21, 22, 22, 22, 22, 22, 22, 21, 20, 21, 21, 21, 21, 21, 21, 20
164 #endif // defined(IS_64BIT)
166 const Bitboard SquaresByColorBB[2] = { BlackSquaresBB, WhiteSquaresBB };
168 const Bitboard FileBB[8] = {
169 FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB
172 const Bitboard NeighboringFilesBB[8] = {
173 FileBBB, FileABB|FileCBB, FileBBB|FileDBB, FileCBB|FileEBB,
174 FileDBB|FileFBB, FileEBB|FileGBB, FileFBB|FileHBB, FileGBB
177 const Bitboard ThisAndNeighboringFilesBB[8] = {
178 FileABB|FileBBB, FileABB|FileBBB|FileCBB,
179 FileBBB|FileCBB|FileDBB, FileCBB|FileDBB|FileEBB,
180 FileDBB|FileEBB|FileFBB, FileEBB|FileFBB|FileGBB,
181 FileFBB|FileGBB|FileHBB, FileGBB|FileHBB
184 const Bitboard RankBB[8] = {
185 Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB
188 const Bitboard RelativeRankBB[2][8] = {
189 { Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB },
190 { Rank8BB, Rank7BB, Rank6BB, Rank5BB, Rank4BB, Rank3BB, Rank2BB, Rank1BB }
193 const Bitboard InFrontBB[2][8] = {
194 { Rank2BB | Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
195 Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
196 Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB,
197 Rank5BB | Rank6BB | Rank7BB | Rank8BB,
198 Rank6BB | Rank7BB | Rank8BB,
206 Rank3BB | Rank2BB | Rank1BB,
207 Rank4BB | Rank3BB | Rank2BB | Rank1BB,
208 Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
209 Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB,
210 Rank7BB | Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB
215 int RAttackIndex[64];
216 Bitboard RAttacks[0x19000];
219 int BAttackIndex[64];
220 Bitboard BAttacks[0x1480];
222 Bitboard SetMaskBB[65];
223 Bitboard ClearMaskBB[65];
225 Bitboard StepAttackBB[16][64];
226 Bitboard RayBB[64][8];
227 Bitboard BetweenBB[64][64];
229 Bitboard PassedPawnMask[2][64];
230 Bitboard OutpostMask[2][64];
232 Bitboard BishopPseudoAttacks[64];
233 Bitboard RookPseudoAttacks[64];
234 Bitboard QueenPseudoAttacks[64];
236 uint8_t BitCount8Bit[256];
240 //// Local definitions
246 void init_ray_bitboards();
248 void init_between_bitboards();
249 Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2],
250 int fmin, int fmax, int rmin, int rmax);
251 Bitboard index_to_bitboard(int index, Bitboard mask);
252 void init_sliding_attacks(Bitboard attacks[],
253 int attackIndex[], Bitboard mask[],
254 const int shift[2], const Bitboard mult[],
256 void init_pseudo_attacks();
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) {
268 for(Rank r = RANK_8; r >= RANK_1; r--) {
269 std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
270 for(File f = FILE_A; f <= FILE_H; f++)
271 std::cout << "| " << (bit_is_set(b, make_square(f, r))? 'X' : ' ') << ' ';
272 std::cout << "|" << std::endl;
274 std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
278 /// init_bitboards() initializes various bitboard arrays. It is called during
279 /// program initialization.
281 void init_bitboards() {
282 int rookDeltas[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};
283 int bishopDeltas[4][2] = {{1,1},{-1,1},{1,-1},{-1,-1}};
285 init_ray_bitboards();
287 init_between_bitboards();
288 init_sliding_attacks(RAttacks, RAttackIndex, RMask, RShift, RMult, rookDeltas);
289 init_sliding_attacks(BAttacks, BAttackIndex, BMask, BShift, BMult, bishopDeltas);
290 init_pseudo_attacks();
294 /// first_1() finds the least significant nonzero bit in a nonzero bitboard.
295 /// pop_1st_bit() finds and clears the least significant nonzero bit in a
296 /// nonzero bitboard.
298 #if defined(IS_64BIT) && !defined(USE_BSFQ)
301 static const int BitTable[64] = {
302 0, 1, 2, 7, 3, 13, 8, 19, 4, 25, 14, 28, 9, 34, 20, 40, 5, 17, 26, 38, 15,
303 46, 29, 48, 10, 31, 35, 54, 21, 50, 41, 57, 63, 6, 12, 18, 24, 27, 33, 39,
304 16, 37, 45, 47, 30, 53, 49, 56, 62, 11, 23, 32, 36, 44, 52, 55, 61, 22, 43,
308 Square first_1(Bitboard b) {
309 return Square(BitTable[((b & -b) * 0x218a392cd3d5dbfULL) >> 58]);
312 Square pop_1st_bit(Bitboard* b) {
315 return Square(BitTable[((bb & -bb) * 0x218a392cd3d5dbfULL) >> 58]);
318 #elif !defined(USE_BSFQ)
321 static const int BitTable[64] = {
322 63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2,
323 51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, 52,
324 26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, 28,
325 58, 20, 37, 17, 36, 8
328 Square first_1(Bitboard b) {
330 uint32_t fold = int(b) ^ int(b >> 32);
331 return Square(BitTable[(fold * 0x783a9b23) >> 26]);
344 // WARNING: Needs -fno-strict-aliasing compiler option
345 Square pop_1st_bit(Bitboard* bb) {
353 *((uint32_t*)bb) = u.dw.l & (u.dw.l - 1);
354 return Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
357 *((uint32_t*)bb+1) = u.dw.h & (u.dw.h - 1); // Little endian only?
358 return Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
365 // All functions below are used to precompute various bitboards during
366 // program initialization. Some of the functions may be difficult to
367 // understand, but they all seem to work correctly, and it should never
368 // be necessary to touch any of them.
371 SetMaskBB[SQ_NONE] = 0ULL;
372 ClearMaskBB[SQ_NONE] = ~SetMaskBB[SQ_NONE];
373 for(Square s = SQ_A1; s <= SQ_H8; s++) {
374 SetMaskBB[s] = (1ULL << s);
375 ClearMaskBB[s] = ~SetMaskBB[s];
377 for(Color c = WHITE; c <= BLACK; c++)
378 for(Square s = SQ_A1; s <= SQ_H8; s++) {
379 PassedPawnMask[c][s] =
380 in_front_bb(c, s) & this_and_neighboring_files_bb(s);
381 OutpostMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
384 for (Bitboard b = 0ULL; b < 256ULL; b++)
385 BitCount8Bit[b] = (uint8_t)count_1s(b);
389 void init_ray_bitboards() {
390 int d[8] = {1, -1, 16, -16, 17, -17, 15, -15};
391 for(int i = 0; i < 128; i = (i + 9) & ~8) {
392 for(int j = 0; j < 8; j++) {
393 RayBB[(i&7)|((i>>4)<<3)][j] = EmptyBoardBB;
394 for(int k = i + d[j]; (k & 0x88) == 0; k += d[j])
395 set_bit(&(RayBB[(i&7)|((i>>4)<<3)][j]), Square((k&7)|((k>>4)<<3)));
401 void init_attacks() {
405 {7,9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0},
406 {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8}, {0}, {0},
407 {-7,-9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0},
408 {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8}
411 for(i = 0; i < 64; i++) {
412 for(j = 0; j <= int(BK); j++) {
413 StepAttackBB[j][i] = EmptyBoardBB;
414 for(k = 0; k < 8 && step[j][k] != 0; k++) {
416 if(l >= 0 && l < 64 && abs((i&7) - (l&7)) < 3)
417 StepAttackBB[j][i] |= (1ULL << l);
424 Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2],
425 int fmin=0, int fmax=7, int rmin=0, int rmax=7) {
426 Bitboard result = 0ULL;
427 int rk = sq / 8, fl = sq % 8, r, f, i;
428 for(i = 0; i < dirs; i++) {
429 int dx = deltas[i][0], dy = deltas[i][1];
430 for(f = fl+dx, r = rk+dy;
431 (dx==0 || (f>=fmin && f<=fmax)) && (dy==0 || (r>=rmin && r<=rmax));
433 result |= (1ULL << (f + r*8));
434 if(block & (1ULL << (f + r*8))) break;
441 void init_between_bitboards() {
442 SquareDelta step[8] = {
443 DELTA_E, DELTA_W, DELTA_N, DELTA_S, DELTA_NE, DELTA_SW, DELTA_NW, DELTA_SE
446 for(Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
447 for(Square s2 = SQ_A1; s2 <= SQ_H8; s2++) {
448 BetweenBB[s1][s2] = EmptyBoardBB;
449 d = signed_direction_between_squares(s1, s2);
450 if(d != SIGNED_DIR_NONE)
451 for(Square s3 = s1 + step[d]; s3 != s2; s3 += step[d])
452 set_bit(&(BetweenBB[s1][s2]), s3);
457 Bitboard index_to_bitboard(int index, Bitboard mask) {
458 int i, j, bits = count_1s(mask);
459 Bitboard result = 0ULL;
460 for(i = 0; i < bits; i++) {
461 j = pop_1st_bit(&mask);
462 if(index & (1 << i)) result |= (1ULL << j);
468 void init_sliding_attacks(Bitboard attacks[],
469 int attackIndex[], Bitboard mask[],
470 const int shift[2], const Bitboard mult[],
472 int i, j, k, index = 0;
474 for(i = 0; i < 64; i++) {
475 attackIndex[i] = index;
476 mask[i] = sliding_attacks(i, 0ULL, 4, deltas, 1, 6, 1, 6);
478 #if defined(IS_64BIT)
479 j = (1 << (64 - shift[i]));
481 j = (1 << (32 - shift[i]));
484 for(k = 0; k < j; k++) {
486 #if defined(IS_64BIT)
487 b = index_to_bitboard(k, mask[i]);
488 attacks[index + ((b * mult[i]) >> shift[i])] =
489 sliding_attacks(i, b, 4, deltas);
491 b = index_to_bitboard(k, mask[i]);
493 (unsigned(int(b) * int(mult[i]) ^
494 int(b >> 32) * int(mult[i] >> 32))
496 sliding_attacks(i, b, 4, deltas);
504 void init_pseudo_attacks() {
506 for(s = SQ_A1; s <= SQ_H8; s++) {
507 BishopPseudoAttacks[s] = bishop_attacks_bb(s, EmptyBoardBB);
508 RookPseudoAttacks[s] = rook_attacks_bb(s, EmptyBoardBB);
509 QueenPseudoAttacks[s] = queen_attacks_bb(s, EmptyBoardBB);