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Reordering magic data

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Gather all magic relevant data into a struct.

This changes memory layout putting everything necessary for processing a single square
in the same memory location thus speeding up access.

Original patch by @snicolet

No functional change.

Closes #1127
Closes #1128
This commit is contained in:
mstembera
2017-06-06 10:20:43 -07:00
committed by Joona Kiiski
parent 6d89d0b64a
commit 659990b43f
2 changed files with 39 additions and 42 deletions
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src/bitboard.h
+23 -17
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@@ -209,41 +209,47 @@ template<> inline int distance<File>(Square x, Square y) { return distance(file_
template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_of(x), rank_of(y)); }
/// Magic holds all magic relevant data for a single square
struct Magic {
Bitboard mask;
Bitboard magic;
Bitboard* attacks;
unsigned shift;
};
/// 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.
template<PieceType Pt>
inline unsigned magic_index(Square s, Bitboard occupied) {
extern Bitboard RookMasks[SQUARE_NB];
extern Bitboard RookMagics[SQUARE_NB];
extern unsigned RookShifts[SQUARE_NB];
extern Bitboard BishopMasks[SQUARE_NB];
extern Bitboard BishopMagics[SQUARE_NB];
extern unsigned BishopShifts[SQUARE_NB];
extern Magic RookMagics[SQUARE_NB];
extern Magic BishopMagics[SQUARE_NB];
Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks;
Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics;
unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts;
const Magic* Magics = Pt == ROOK ? RookMagics : BishopMagics;
Bitboard mask = Magics[s].mask;
Bitboard magic = Magics[s].magic;
unsigned shift = Magics[s].shift;
if (HasPext)
return unsigned(pext(occupied, Masks[s]));
return unsigned(pext(occupied, mask));
if (Is64Bit)
return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]);
return unsigned(((occupied & mask) * magic) >> shift);
unsigned lo = unsigned(occupied) & unsigned(Masks[s]);
unsigned hi = unsigned(occupied >> 32) & unsigned(Masks[s] >> 32);
return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
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) {
extern Bitboard* RookAttacks[SQUARE_NB];
extern Bitboard* BishopAttacks[SQUARE_NB];
extern Magic RookMagics[SQUARE_NB];
extern Magic BishopMagics[SQUARE_NB];
return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index<Pt>(s, occupied)];
return (Pt == ROOK ? RookMagics : BishopMagics)[s].attacks[magic_index<Pt>(s, occupied)];
}
inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {