const uint64_t DeBruijn64 = 0x3F79D71B4CB0A89ULL;
const uint32_t DeBruijn32 = 0x783A9B23;
- int MS1BTable[256]; // To implement software msb()
+ int MSBTable[256]; // To implement software msb()
Square BSFTable[SQUARE_NB]; // To implement software bitscan
Bitboard RookTable[0x19000]; // To store rook attacks
Bitboard BishopTable[0x1480]; // To store bishop attacks
// bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses
// Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch.
- FORCE_INLINE unsigned bsf_index(Bitboard b) {
+ unsigned bsf_index(Bitboard b) {
b ^= b - 1;
return Is64Bit ? (b * DeBruijn64) >> 58
: ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26;
result += 8;
}
- return Square(result + MS1BTable[b32]);
+ return Square(result + MSBTable[b32]);
}
#endif // ifndef USE_BSFQ
for (Rank r = RANK_8; r >= RANK_1; --r)
{
for (File f = FILE_A; f <= FILE_H; ++f)
- s.append(b & make_square(f, r) ? "| X " : "| ");
+ s += b & make_square(f, r) ? "| X " : "| ";
- s.append("|\n+---+---+---+---+---+---+---+---+\n");
+ s += "|\n+---+---+---+---+---+---+---+---+\n";
}
return s;
BSFTable[bsf_index(SquareBB[s])] = s;
}
- for (Bitboard b = 1; b < 256; ++b)
- MS1BTable[b] = more_than_one(b) ? MS1BTable[b - 1] : lsb(b);
+ for (Bitboard b = 2; b < 256; ++b)
+ MSBTable[b] = MSBTable[b - 1] + !more_than_one(b);
for (File f = FILE_A; f <= FILE_H; ++f)
FileBB[f] = f > FILE_A ? FileBB[f - 1] << 1 : FileABB;
PseudoAttacks[QUEEN][s1] = PseudoAttacks[BISHOP][s1] = attacks_bb<BISHOP>(s1, 0);
PseudoAttacks[QUEEN][s1] |= PseudoAttacks[ ROOK][s1] = attacks_bb< ROOK>(s1, 0);
- for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
- {
- Piece pc = (PseudoAttacks[BISHOP][s1] & s2) ? W_BISHOP :
- (PseudoAttacks[ROOK][s1] & s2) ? W_ROOK : NO_PIECE;
-
- if (pc == NO_PIECE)
- continue;
+ for (Piece pc = W_BISHOP; pc <= W_ROOK; ++pc)
+ for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
+ {
+ if (!(PseudoAttacks[pc][s1] & s2))
+ continue;
- LineBB[s1][s2] = (attacks_bb(pc, s1, 0) & attacks_bb(pc, s2, 0)) | s1 | s2;
- BetweenBB[s1][s2] = attacks_bb(pc, s1, SquareBB[s2]) & attacks_bb(pc, s2, SquareBB[s1]);
- }
+ LineBB[s1][s2] = (attacks_bb(pc, s1, 0) & attacks_bb(pc, s2, 0)) | s1 | s2;
+ BetweenBB[s1][s2] = attacks_bb(pc, s1, SquareBB[s2]) & attacks_bb(pc, s2, SquareBB[s1]);
+ }
}
}
{ 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } };
Bitboard occupancy[4096], reference[4096], edges, b;
- int i, size;
+ int age[4096], current = 0, i, size;
+
+ std::memset(age, 0, sizeof(age));
// attacks[s] is a pointer to the beginning of the attacks table for square 's'
attacks[SQ_A1] = table;
magics[s] = rng.sparse_rand<Bitboard>();
while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
- std::memset(attacks[s], 0, size * sizeof(Bitboard));
-
// A good magic must map every possible occupancy to an index that
// looks up the correct sliding attack in the attacks[s] database.
// Note that we build up the database for square 's' as a side
// effect of verifying the magic.
- for (i = 0; i < size; ++i)
+ for (++current, i = 0; i < size; ++i)
{
- Bitboard& attack = attacks[s][index(s, occupancy[i])];
-
- if (attack && attack != reference[i])
+ unsigned idx = index(s, occupancy[i]);
+
+ if (age[idx] < current)
+ {
+ age[idx] = current;
+ attacks[s][idx] = reference[i];
+ }
+ else if (attacks[s][idx] != reference[i])
break;
-
- assert(reference[i]);
-
- attack = reference[i];
}
} while (i < size);
}