What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?

Question

If I have some integer n, and I want to know the position of the most significant bit (that is, if the least significant bit is on the right, I want to know the position of

Answer 1

A version in C using successive approximation:

unsigned int getMsb(unsigned int n)
{
  unsigned int msb  = sizeof(n) * 4;
  unsigned int step = msb;
  while (step > 1)
 {
    step /=2;
    if (n>>msb)
     msb += step;
   else
     msb -= step;
 }
  if (n>>msb)
    msb++;
  return (msb - 1);
}

Advantage: the running time is constant regardless of the provided number, as the number of loops are always the same. ( 4 loops when using "unsigned int")