1int
2ffs (x)
3     int x;
4{
5  int bit, mask;
6
7  if (x == 0)
8    return 0;
9
10  for (bit = 1, mask = 1; !(x & mask); bit++, mask <<= 1)
11    ;
12
13  return bit;
14}
15
16f (x)
17     int x;
18{
19  int y;
20  y = ffs (x) - 1;
21  if (y < 0)
22    abort ();
23}
24
25main ()
26{
27  f (1);
28  exit (0);
29}
30