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Rename first_1 / last_1 in lsb / msb

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It seems more accurate: lsb is clear while 'first
bit' depends from where you look at the bitboard.

And fix compile in case of 64 bits platforms that
do not use BSFQ intrinsics.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2012-07-08 08:30:37 +01:00
parent 67d91dfd50
commit 6b5322ce00
12 changed files with 66 additions and 70 deletions
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45
src/bitboard.h
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@@ -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