cosmopolitan/libc/nexgen32e/bsf.h

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#ifndef COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_
#define COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
/*
* BIT SCANNING 101
* ctz(𝑥) 31^clz(𝑥) clz(𝑥)
* uint32 𝑥 bsf(𝑥) tzcnt(𝑥) ffs(𝑥) bsr(𝑥) lzcnt(𝑥)
* 0x00000000 wut 32 0 wut 32
* 0x00000001 0 0 1 0 31
* 0x80000001 0 0 1 31 0
* 0x80000000 31 31 32 31 0
* 0x00000010 4 4 5 4 27
* 0x08000010 4 4 5 27 4
* 0x08000000 27 27 28 27 4
* 0xffffffff 0 0 1 31 0
*/
int bsf(int);
int bsfl(long);
int bsfll(long long);
int bsfmax(uintmax_t);
#ifdef __GNUC__
#define bsf(u) __builtin_ctz(u)
#define bsfl(u) __builtin_ctzl(u)
#define bsfll(u) __builtin_ctzll(u)
#endif
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_NEXGEN32E_BSF_H_ */