Fastest way to enumerate through turned on bits of an integer

Question

What\'s the fastest way to enumerate through an integer and return the exponent of each bit that is turned on? Have seen an example using << and another u

Answer 1

If you won't choke on a little C++:

 void func(int i, int& n, int a[]){
  n = 0;
  if (i < 0) a[n++] = 31;
  i <<= 1;
  if (i < 0) a[n++] = 30;
  i <<= 1;
  if (i < 0) a[n++] = 29;
  i <<= 1;

  ...

  if (i < 0) a[n++] = 0;
}