HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-19 00:26:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

Retire bitScanReverse32()

Browse Source 
Use log() instead because we are not in speed
critical paths.

Also a bit of renaming and code shuffle while there.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2010-06-01 21:28:45 +01:00
parent 50e094ef8d
commit 5212995563
3 changed files with 45 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/bitboard.cpp
View File

@@ -373,39 +373,6 @@ Square pop_1st_bit(Bitboard* bb) {
#endif
// Optimized bitScanReverse32() implementation by Pascal Georges. Note
// that first bit is 1, this allow to differentiate between 0 and 1.
static CACHE_LINE_ALIGNMENT
const char MsbTable[256] = {
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
};
int bitScanReverse32(uint32_t b)
{
int result = 0;
if (b > 0xFFFF)
{
b >>= 16;
result += 16;
}
if (b > 0xFF)
{
b >>= 8;
result += 8;
}
return result + MsbTable[b];
}
namespace {