Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
}
-/// first_1() finds the least significant nonzero bit in a nonzero bitboard.
-/// pop_1st_bit() finds and clears the least significant nonzero bit in a
-/// nonzero bitboard.
+/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
+/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
-#if defined(IS_64BIT) && !defined(USE_BSFQ)
+#if !defined(USE_BSFQ)
-Square first_1(Bitboard b) {
- return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
-}
-
-Square pop_1st_bit(Bitboard* b) {
- Bitboard bb = *b;
- *b &= (*b - 1);
- return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
-}
+Square lsb(Bitboard b) {
-#elif !defined(USE_BSFQ)
+ if (Is64Bit)
+ return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
-Square first_1(Bitboard b) {
b ^= (b - 1);
uint32_t fold = unsigned(b) ^ unsigned(b >> 32);
return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
}
-Square pop_1st_bit(Bitboard* b) {
+Square pop_lsb(Bitboard* b) {
Bitboard bb = *b;
*b = bb & (bb - 1);
+
+ if (Is64Bit)
+ return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
+
bb ^= (bb - 1);
uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32);
return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
}
-Square last_1(Bitboard b) {
+Square msb(Bitboard b) {
unsigned b32;
int result = 0;