typedef unsigned short uint16_t; typedef unsigned int uint32_t; #define CF (1<<0) #define PF (1<<2) #define AF (1<<4) #define ZF (1<<6) #define SF (1<<7) #define OF (1<<11) #define EFLAGS_BITS (CF|PF|AF|ZF|SF|OF) void test16(uint16_t x, uint32_t eflags) { uint16_t bsr_result; uint32_t bsr_eflags; uint16_t bsf_result; uint32_t bsf_eflags; __asm volatile("" : "=&r" (bsr_result), "=&r" (bsr_eflags) : "r" (x), "i" (~EFLAGS_BITS), "r" (eflags)); __asm volatile("" : "=&r" (bsf_result), "=&r" (bsf_eflags) : "r" (x), "i" (~EFLAGS_BITS), "r" (eflags)); printf("%08x %04x bsrw %02x %08x bsfw %02x %08x\n", x, eflags, bsr_result, bsr_eflags, bsf_result, bsf_eflags); }