/*FUNCTION	<<ffs>>---find first bit set in a wordINDEX	ffsANSI_SYNOPSIS	int ffs(int <[word]>);TRAD_SYNOPSIS	int ffs(<[word]>);DESCRIPTION<<ffs>> returns the first bit set in a word.RETURNS<<ffs>> returns 0 if <[c]> is 0, 1 if <[c]> is odd, 2 if <[c]> is a multiple of2, etc.PORTABILITY<<ffs>> is not ANSI C.No supporting OS subroutines are required.  */#include <_ansi.h>int_DEFUN(ffs, (word),       int word){  int i;  if (!word)    return 0;  i = 0;  for (;;)    {      if (((1 << i++) & word) != 0)	return i;    }}