cmov

inline int32_t cmov_nz(uint32_t val)
{
#if defined(__GNUC__)
  uint32_t ret;
  __asm__
  (
    "       .att_syntax   noprefix  \n\t"
    "cmp             $0,  %1        \n\t"
    "mov    $0xffffffff,  %%ecx     \n\t"  // -1
    "xor          %%eax,  %%eax     \n\t"  //  0
    "cmovnz       %%ecx,  %%eax     \n\t"
	"mov          %%eax,  %0        \n\t"  // ret = %eax
	: "=g" (ret)
	: "g" (val)
	: "eax", "ecx", "cc"
  );
  return (int32_t)ret;
#else
  const int32_t v = (int32_t) val;
  return (int32_t)((1 & ((uint32_t)(v - 1) >> 8)) - 1);
#endif
}