Bitboard magic;
Bitboard* attacks;
unsigned shift;
+
+ /// looks up the index using the 'magic bitboards' approach.
+ unsigned index(Bitboard occupied) const {
+
+ if (HasPext)
+ return unsigned(pext(occupied, mask));
+
+ 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;
+ }
};
extern Magic RookMagics[SQUARE_NB];
/// attacks_bb() returns a bitboard representing all the squares attacked by a
-/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index()
-/// looks up the index using the 'magic bitboards' approach.
-inline unsigned magic_index(const Magic& m, Bitboard occupied) {
-
- if (HasPext)
- return unsigned(pext(occupied, m.mask));
-
- if (Is64Bit)
- return unsigned(((occupied & m.mask) * m.magic) >> m.shift);
-
- unsigned lo = unsigned(occupied) & unsigned(m.mask);
- unsigned hi = unsigned(occupied >> 32) & unsigned(m.mask >> 32);
- return (lo * unsigned(m.magic) ^ hi * unsigned(m.magic >> 32)) >> m.shift;
-}
+/// piece of type Pt (bishop or rook) placed on 's'.
template<PieceType Pt>
inline Bitboard attacks_bb(Square s, Bitboard occupied) {
const Magic& M = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
- return M.attacks[magic_index(M, occupied)];
+ return M.attacks[M.index(occupied)];
}
inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {