#if defined(IS_64BIT) && !defined(USE_BSFQ)
-CACHE_LINE_ALIGNMENT
-static const int BitTable[64] = {
+static CACHE_LINE_ALIGNMENT
+const int BitTable[64] = {
0, 1, 2, 7, 3, 13, 8, 19, 4, 25, 14, 28, 9, 34, 20, 40, 5, 17, 26, 38, 15,
46, 29, 48, 10, 31, 35, 54, 21, 50, 41, 57, 63, 6, 12, 18, 24, 27, 33, 39,
16, 37, 45, 47, 30, 53, 49, 56, 62, 11, 23, 32, 36, 44, 52, 55, 61, 22, 43,
Square pop_1st_bit(Bitboard* bb) {
- b_union* u;
+ b_union u;
Square ret;
- u = (b_union*)bb;
+ u.b = *bb;
- if (u->dw.l)
+ if (u.dw.l)
{
- ret = Square(BitTable[((u->dw.l ^ (u->dw.l - 1)) * 0x783a9b23) >> 26]);
- u->dw.l &= (u->dw.l - 1);
+ ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
+ u.dw.l &= (u.dw.l - 1);
+ *bb = u.b;
return ret;
}
- ret = Square(BitTable[((~(u->dw.h ^ (u->dw.h - 1))) * 0x783a9b23) >> 26]);
- u->dw.h &= (u->dw.h - 1);
+ ret = Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
+ u.dw.h &= (u.dw.h - 1);
+ *bb = u.b;
return ret;
}
#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 {
// All functions below are used to precompute various bitboards during