libgcrypt get_cpuid() 内联汇编有 bug

代码:
#define NULL ((void*)0)



static void

get_cpuid(unsigned int in, unsigned int *eax, unsigned int *ebx,

          unsigned int *ecx, unsigned int *edx)

{

  unsigned int regs[4];



  asm volatile

    ("movl %%ebx, %%edi\n\t"     /* Save GOT register.  */

     "xorl %%ebx, %%ebx\n\t"

     "cpuid\n\t"

     "movl %%ebx, %1\n\t"

     "movl %%edi, %%ebx\n\t"     /* Restore GOT register. */

     : "=a" (regs[0]), "=g" (regs[1]), "=c" (regs[2]), "=d" (regs[3])

     : "0" (in), "2" (0), "3" (0)

     : "cc", "edi"

     );



  if (eax)

    *eax = regs[0];

  if (ebx)

    *ebx = regs[1];

  if (ecx)

    *ecx = regs[2];

  if (edx)

    *edx = regs[3];

}



unsigned int feature_detect()

{

  unsigned int fms, family, model, features, features2;

  unsigned int result = 0;



  get_cpuid(1, &fms, NULL, &features, &features2);

  family = ((fms & 0xf00) >> 8) + ((fms & 0xff00000) >> 20);

  model = ((fms & 0xf0) >> 4) + ((fms & 0xf0000) >> 12);



  if (family == 6) {

    if (model == 0x3a) {

      result |= 1;

    }

    get_cpuid(7, NULL, &features, NULL, NULL);

    // in my machine features=0x281

    if (features & 0x00000001) {

      result |= 2;

    }

  }

  return result;

}



int main()

{

  return feature_detect();

}