pop (x) int x;
pop (int x)
pop (x)     int x;{  /* We assume that no more than 16 bits are used.  */  x = ((x & ~0x5555) >> 1) + (x & 0x5555);  x = ((x & ~0x3333) >> 2) + (x & 0x3333);  x = ((x >> 4) + x) & 0x0f0f;  x = ((x >> 8) + x) & 0xff;  return x;}