xref: /titanic_51/usr/src/boot/lib/libc/string/fls.c (revision 4a5d661a82b942b6538acd26209d959ce98b593a)
1*4a5d661aSToomas Soome /*-
2*4a5d661aSToomas Soome  * Copyright (c) 1990, 1993
3*4a5d661aSToomas Soome  *	The Regents of the University of California.  All rights reserved.
4*4a5d661aSToomas Soome  *
5*4a5d661aSToomas Soome  * Redistribution and use in source and binary forms, with or without
6*4a5d661aSToomas Soome  * modification, are permitted provided that the following conditions
7*4a5d661aSToomas Soome  * are met:
8*4a5d661aSToomas Soome  * 1. Redistributions of source code must retain the above copyright
9*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer.
10*4a5d661aSToomas Soome  * 2. Redistributions in binary form must reproduce the above copyright
11*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer in the
12*4a5d661aSToomas Soome  *    documentation and/or other materials provided with the distribution.
13*4a5d661aSToomas Soome  * 3. Neither the name of the University nor the names of its contributors
14*4a5d661aSToomas Soome  *    may be used to endorse or promote products derived from this software
15*4a5d661aSToomas Soome  *    without specific prior written permission.
16*4a5d661aSToomas Soome  *
17*4a5d661aSToomas Soome  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18*4a5d661aSToomas Soome  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19*4a5d661aSToomas Soome  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20*4a5d661aSToomas Soome  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21*4a5d661aSToomas Soome  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22*4a5d661aSToomas Soome  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23*4a5d661aSToomas Soome  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24*4a5d661aSToomas Soome  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25*4a5d661aSToomas Soome  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26*4a5d661aSToomas Soome  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*4a5d661aSToomas Soome  * SUCH DAMAGE.
28*4a5d661aSToomas Soome  */
29*4a5d661aSToomas Soome 
30*4a5d661aSToomas Soome #include <sys/cdefs.h>
31*4a5d661aSToomas Soome __FBSDID("$FreeBSD$");
32*4a5d661aSToomas Soome 
33*4a5d661aSToomas Soome #include <strings.h>
34*4a5d661aSToomas Soome 
35*4a5d661aSToomas Soome /*
36*4a5d661aSToomas Soome  * Find Last Set bit
37*4a5d661aSToomas Soome  */
38*4a5d661aSToomas Soome int
39*4a5d661aSToomas Soome fls(int mask)
40*4a5d661aSToomas Soome {
41*4a5d661aSToomas Soome 	int bit;
42*4a5d661aSToomas Soome 
43*4a5d661aSToomas Soome 	if (mask == 0)
44*4a5d661aSToomas Soome 		return (0);
45*4a5d661aSToomas Soome 	for (bit = 1; mask != 1; bit++)
46*4a5d661aSToomas Soome 		mask = (unsigned int)mask >> 1;
47*4a5d661aSToomas Soome 	return (bit);
48*4a5d661aSToomas Soome }
49