}
-/// 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(USE_BSFQ)
-#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
+# if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
-FORCE_INLINE Square first_1(Bitboard b) {
+FORCE_INLINE Square lsb(Bitboard b) {
unsigned long index;
_BitScanForward64(&index, b);
return (Square) index;
}
-FORCE_INLINE Square last_1(Bitboard b) {
+FORCE_INLINE Square msb(Bitboard b) {
unsigned long index;
_BitScanReverse64(&index, b);
return (Square) index;
}
-#else
-FORCE_INLINE Square first_1(Bitboard b) { // Assembly code by Heinz van Saanen
- Bitboard dummy;
- __asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
- return (Square) dummy;
+# else
+
+FORCE_INLINE Square lsb(Bitboard b) { // Assembly code by Heinz van Saanen
+ Bitboard index;
+ __asm__("bsfq %1, %0": "=r"(index): "rm"(b) );
+ return (Square) index;
}
-FORCE_INLINE Square last_1(Bitboard b) {
- Bitboard dummy;
- __asm__("bsrq %1, %0": "=r"(dummy): "rm"(b) );
- return (Square) dummy;
+FORCE_INLINE Square msb(Bitboard b) {
+ Bitboard index;
+ __asm__("bsrq %1, %0": "=r"(index): "rm"(b) );
+ return (Square) index;
}
-#endif
-FORCE_INLINE Square pop_1st_bit(Bitboard* b) {
- const Square s = first_1(*b);
- *b &= ~(1ULL<<s);
+# endif
+
+FORCE_INLINE Square pop_lsb(Bitboard* b) {
+ const Square s = lsb(*b);
+ *b &= ~(1ULL << s);
return s;
}
#else // if !defined(USE_BSFQ)
-extern Square first_1(Bitboard b);
-extern Square last_1(Bitboard b);
-extern Square pop_1st_bit(Bitboard* b);
+extern Square msb(Bitboard b);
+extern Square lsb(Bitboard b);
+extern Square pop_lsb(Bitboard* b);
#endif