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Switch to hardware PEXT

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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
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@@ -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];