The While Version

int Russian(int a, int b)
//  implements Russian Peasant Algorithm
{
   int x = a, y = b, z = 0;
   while (x > 0)
   {
      if ( 1 == x % 2)
         z += y;
      y <<= 1;
      x >>= 1;
   }
   return z;        
}

This is the first one we saw. How can we analyze it?