Rename first_1 / last_1 in lsb / msb

[stockfish] / src / bitboard.h

diff --git a/src/bitboard.h b/src/bitboard.h
index d187102ff1bf17914dd806c250b85bf8d757049f..2c4a0ea299f6896e739b7a0bec3291a70bbc1995 100644 (file)
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -221,51 +221,52 @@ inline Bitboard attacks_bb(Square s, Bitboard occ) {
 }
 
 
-/// 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