1  /* ffs -- Find the first bit set in the parameter
       2  
       3  @deftypefn Supplemental int ffs (int @var{valu})
       4  
       5  Find the first (least significant) bit set in @var{valu}.  Bits are
       6  numbered from right to left, starting with bit 1 (corresponding to the
       7  value 1).  If @var{valu} is zero, zero is returned.
       8  
       9  @end deftypefn
      10  
      11  */
      12  
      13  int
      14  ffs (register int valu)
      15  {
      16    register int bit;
      17  
      18    if (valu == 0)
      19      return 0;
      20  
      21    for (bit = 1; !(valu & 1); bit++)
      22    	valu >>= 1;
      23  
      24    return bit;
      25  }
      26