void init_magics(Bitboard table[], Magic magics[], Square deltas[]) {
+ // Optimal PRNG seeds to pick the correct magics in the shortest time
int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998, 5731, 95205, 104912, 17020 },
{ 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } };
Bitboard* attacks;
unsigned shift;
- /// looks up the index using the 'magic bitboards' approach.
+ // Compute the attack's index using the 'magic bitboards' approach
unsigned index(Bitboard occupied) const {
- if (HasPext)
- return unsigned(pext(occupied, mask));
+ if (HasPext)
+ return unsigned(pext(occupied, mask));
- if (Is64Bit)
- return unsigned(((occupied & mask) * magic) >> shift);
+ if (Is64Bit)
+ return unsigned(((occupied & mask) * magic) >> shift);
- unsigned lo = unsigned(occupied) & unsigned(mask);
- unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
- return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
+ unsigned lo = unsigned(occupied) & unsigned(mask);
+ unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
+ return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
}
};
template<PieceType Pt>
inline Bitboard attacks_bb(Square s, Bitboard occupied) {
- const Magic& M = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
- return M.attacks[M.index(occupied)];
+ const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
+ return m.attacks[m.index(occupied)];
}
inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {