cosmopolitan/libc/intrin/bsf.h
2023-05-10 04:20:46 -07:00

35 lines
1.3 KiB
C

#ifndef COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_
#define COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
int _bsf(int) pureconst;
int _bsfl(long) pureconst;
int _bsfll(long long) pureconst;
int _bsf128(uintmax_t) pureconst;
#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
#ifdef __x86_64__
#define _bsf(u) \
({ \
unsigned BiTs; \
asm("bsf\t%0,%0" : "=r"(BiTs) : "0"((unsigned)(u)) : "cc"); \
BiTs; \
})
#define _bsfl(u) \
({ \
unsigned long BiTs; \
asm("bsf\t%0,%0" : "=r"(BiTs) : "0"((unsigned long)(u)) : "cc"); \
(unsigned)BiTs; \
})
#define _bsfll(u) _bsfl(u)
#else
#define _bsf(x) __builtin_ctz(x)
#define _bsfl(x) __builtin_ctzl(x)
#define _bsfll(x) __builtin_ctzll(x)
#endif
#endif
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_ */