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Retire run-time detection of hardware POPCNT

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It was meant to build a single binary optimized
for any kind of CPU: with and without hardware POPCNT.

This is a nice idea but in practice was never used, or
people builds binary with popcnt enabled or not, mainly
according to their type of CPU. And it was also never
used in the official Jim's builds where, in case, would
be easier for a number of reasons, do build two different
versions: with and without SEE42 support.

So retire this feature and simplify the code.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-12-30 11:30:26 +01:00
parent 20a6f99cdb
commit 0a6532a39d
6 changed files with 56 additions and 74 deletions
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6
src/bitboard.cpp
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@@ -198,7 +198,7 @@ void bitboards_init() {
SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2));
for (int i = 0; i < 64; i++)
if (!CpuIs64Bit) // Matt Taylor's folding trick for 32 bit systems
if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems
{
Bitboard b = 1ULL << i;
b ^= b - 1;
@@ -321,7 +321,7 @@ namespace {
// the number of 1s of the mask. Hence we deduce the size of the shift to
// apply to the 64 or 32 bits word to get the index.
masks[s] = sliding_attacks(pt, s, 0) & ~edges;
shifts[s] = (CpuIs64Bit ? 64 : 32) - count_1s<CNT32_MAX15>(masks[s]);
shifts[s] = (Is64Bit ? 64 : 32) - count_1s<CNT32_MAX15>(masks[s]);
// Use Carry-Rippler trick to enumerate all subsets of masks[s] and
// store the corresponding sliding attacks bitboard in reference[].
@@ -337,7 +337,7 @@ namespace {
if (s < SQ_H8)
attacks[s + 1] = attacks[s] + size;
booster = MagicBoosters[CpuIs64Bit][rank_of(s)];
booster = MagicBoosters[Is64Bit][rank_of(s)];
// Find a magic for square 's' picking up an (almost) random number
// until we find the one that passes the verification test.