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Retire BitCount8Bit[] table

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Use popcount() instead in the only calling place.
It is used only at initialization so there is no
speed regression and anyhow even initialization
itself is not slowed down: magic bitboard setup
stays around 175 msec on my slow 32bit Core Duo.

No functional change.
This commit is contained in:
Marco Costalba
2012-10-13 14:21:27 +02:00
parent c2cd75843e
commit d023be5a21
1 changed files with 1 additions and 5 deletions
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6
src/bitboard.cpp
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@@ -66,7 +66,6 @@ namespace {
Square BSFTable[64];
Bitboard RTable[0x19000]; // Storage space for rook attacks
Bitboard BTable[0x1480]; // Storage space for bishop attacks
uint8_t BitCount8Bit[256];
typedef unsigned (Fn)(Square, Bitboard);
@@ -159,9 +158,6 @@ void Bitboards::init() {
for (int i = 0; i < 64; i++)
BSFTable[bsf_index(1ULL << i)] = Square(i);
for (Bitboard b = 0; b < 256; b++)
BitCount8Bit[b] = (uint8_t)popcount<Max15>(b);
for (Square s = SQ_A1; s <= SQ_H8; s++)
SquareBB[s] = 1ULL << s;
@@ -324,7 +320,7 @@ namespace {
// until we find the one that passes the verification test.
do {
do magics[s] = pick_random(rk, booster);
while (BitCount8Bit[(magics[s] * masks[s]) >> 56] < 6);
while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
memset(attacks[s], 0, size * sizeof(Bitboard));