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Switch to hardware PEXT

Browse source 
Retire software pext and introduce hardware
call when USE_PEXT is defined during compilation.

This is a full complete implementation of sliding
attacks using PEXT.

No functional change.
This commit is contained in:
Marco Costalba 2014-04-07 21:04:34 +02:00
parent c556fe1d71
commit da2f8880b9
3 changed files with 8 additions and 21 deletions
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19
src/bitboard.cpp
View file

@ -79,23 +79,6 @@ namespace {
}
}
/// Intel PEXT (parallel extraction) software implementation
Bitboard pext(Bitboard b, Bitboard mask) {
Bitboard res = 0;
for (Bitboard bb = 1; mask; bb += bb)
{
if (b & mask & -mask)
res |= bb;
mask &= mask - 1;
}
return res;
}
/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
@ -299,7 +282,7 @@ namespace {
reference[size] = sliding_attack(deltas, s, b);
if (HasPext)
attacks[s][pext(occupancy[size], masks[s])] = reference[size];
attacks[s][_pext_u64(b, masks[s])] = reference[size];
size++;
b = (b - masks[s]) & masks[s];

4
src/bitboard.h
View file

@ -23,8 +23,6 @@
#include "types.h"
extern Bitboard pext(Bitboard b, Bitboard mask);
namespace Bitboards {
void init();
@ -244,7 +242,7 @@ FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
if (HasPext)
return unsigned(pext(occ, Masks[s]));
return unsigned(_pext_u64(occ, Masks[s]));
if (Is64Bit)
return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);

6
src/types.h
View file

@ -54,6 +54,12 @@
# include <nmmintrin.h> // Intel header for _mm_popcnt_u64() intrinsic
#endif
#if defined(USE_PEXT)
# include <x86intrin.h> // Gcc header for _pext_u64() intrinsic
#else
# define _pext_u64(b, m) (0)
#endif
# if !defined(NO_PREFETCH) && (defined(__INTEL_COMPILER) || defined(_MSC_VER))
# include <xmmintrin.h> // Intel and Microsoft header for _mm_prefetch()
# endif