toolchain/gcc/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 (valu)
  15   register int valu;
  16 {
  17   register int bit;
  18
  19   if (valu == 0)
  20     return 0;
  21
  22   for (bit = 1; !(valu & 1); bit++)
  23         valu >>= 1;
  24
  25   return bit;
  26 }
  27