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Magic::index()

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Make magic_index() a member of Magic since it uses all it's members
and keep us from having to pass the function pointer around to
init_magics().

No functional change

Closes #1146
This commit is contained in:
mstembera
2017-06-28 17:11:17 -07:00
committed by Joona Kiiski
parent 7e897a64f2
commit 69eb391cd7
2 changed files with 21 additions and 22 deletions
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31
src/bitboard.h
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@@ -82,6 +82,20 @@ struct Magic {
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];
@@ -222,26 +236,13 @@ template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_
/// 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) {