sdcc/support/sdbinutils/libiberty/ffs.c

   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