Function ffs

freebsd/libkern/ffs.c:40–50

* Find First Set bit */

 * Find First Set bit
 */
int
ffs(int mask)
{
	int bit;

	if (mask == 0)
		return (0);
	for (bit = 1; !(mask & 1); bit++)
		mask = (unsigned int)mask >> 1;
	return (bit);
}