Function fls

freebsd/libkern/fls.c:40–50

* Find Last Set bit */

 * Find Last Set bit
 */
int
fls(int mask)
{
	int bit;

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