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Skip offset calculation in slider attacks

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Another small simplification and micro optimization.

No functional change in both 32 and 64 bits.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-06-05 14:41:59 +01:00
parent 670cee44f0
commit b1b0c64046
2 changed files with 19 additions and 21 deletions
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25
src/bitboard.cpp
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@@ -24,9 +24,6 @@
// Global bitboards definitions with static storage duration are
// automatically set to zero before enter main().
Bitboard RAttacks[0x19000];
Bitboard BAttacks[0x1480];
Magics RMagics[64];
Magics BMagics[64];
@@ -53,6 +50,15 @@ uint8_t BitCount8Bit[256];
namespace {
CACHE_LINE_ALIGNMENT
int BSFTable[64];
Bitboard RAttacks[0x19000];
Bitboard BAttacks[0x1480];
void init_sliding_attacks(Bitboard attacks[], Magics m[], const Bitboard mult[], Square deltas[]);
#if defined(IS_64BIT)
const uint64_t DeBruijnMagic = 0x218A392CD3D5DBFULL;
@@ -163,9 +169,6 @@ const uint64_t RMult[64] = {
#endif // defined(IS_64BIT)
CACHE_LINE_ALIGNMENT int BSFTable[64];
void init_sliding_attacks(Bitboard attacks[], Magics m[], const Bitboard mult[], Square deltas[]);
}
@@ -397,10 +400,10 @@ namespace {
{
excluded = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s));
m[s].offset = offset;
m[s].mult = mult[s];
m[s].mask = sliding_attacks(s, EmptyBoardBB, deltas, excluded);
m[s].shift = (CpuIs64Bit ? 64 : 32) - count_1s<CNT64>(m[s].mask);
m[s].attacks = &attacks[offset];
m[s].mult = mult[s];
m[s].mask = sliding_attacks(s, EmptyBoardBB, deltas, excluded);
m[s].shift = (CpuIs64Bit ? 64 : 32) - count_1s<CNT64>(m[s].mask);
maxKey = 1 << count_1s<CNT64>(m[s].mask);
@@ -411,7 +414,7 @@ namespace {
index = CpuIs64Bit ? occupancy * mult[s]
: unsigned(occupancy * mult[s] ^ (occupancy >> 32) * (mult[s] >> 32));
attacks[offset + (index >> m[s].shift)] = sliding_attacks(s, occupancy, deltas, EmptyBoardBB);
m[s].attacks[index >> m[s].shift] = sliding_attacks(s, occupancy, deltas, EmptyBoardBB);
}
offset += maxKey;
}