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Speedup sliders attacks for 32bit CPU

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Replace a 64 bit 'and' by two 32 bits ones and
use unsigned instead of int.

This simple patch increases perft speed of 6% on
my Intel Core 2 Duo !

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2012-02-12 15:12:01 +01:00
parent b1768c115c
commit 099b5e45e6
2 changed files with 12 additions and 10 deletions
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14
src/bitboard.h
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@@ -28,12 +28,12 @@ CACHE_LINE_ALIGNMENT
extern Bitboard RMasks[64];
extern Bitboard RMagics[64];
extern Bitboard* RAttacks[64];
extern int RShifts[64];
extern unsigned RShifts[64];
extern Bitboard BMasks[64];
extern Bitboard BMagics[64];
extern Bitboard* BAttacks[64];
extern int BShifts[64];
extern unsigned BShifts[64];
extern Bitboard SquareBB[64];
extern Bitboard FileBB[8];
@@ -134,13 +134,15 @@ FORCE_INLINE unsigned b_index(Square s, Bitboard occ) {
#else // if !defined(IS_64BIT)
FORCE_INLINE unsigned r_index(Square s, Bitboard occ) {
Bitboard b = occ & RMasks[s];
return unsigned(int(b) * int(RMagics[s]) ^ int(b >> 32) * int(RMagics[s] >> 32)) >> RShifts[s];
unsigned lo = unsigned(occ) & unsigned(RMasks[s]);
unsigned hi = unsigned(occ >> 32) & unsigned(RMasks[s] >> 32);
return (lo * unsigned(RMagics[s]) ^ hi * unsigned(RMagics[s] >> 32)) >> RShifts[s];
}
FORCE_INLINE unsigned b_index(Square s, Bitboard occ) {
Bitboard b = occ & BMasks[s];
return unsigned(int(b) * int(BMagics[s]) ^ int(b >> 32) * int(BMagics[s] >> 32)) >> BShifts[s];
unsigned lo = unsigned(occ) & unsigned(BMasks[s]);
unsigned hi = unsigned(occ >> 32) & unsigned(BMasks[s] >> 32);
return (lo * unsigned(BMagics[s]) ^ hi * unsigned(BMagics[s] >> 32)) >> BShifts[s];
}
#endif