20000523-1.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

int
main (void)
{
  long long   x;
  int         n;

  if (sizeof (long long) < 64)
    exit (0);
  
  n = 9;
  x = (((long long) n) << 55) / 0xff; 

  if (x == 0)
    abort ();

  x = (((long long) 9) << 55) / 0xff;

  if (x == 0)
    abort ();

  exit (0);
}