1*22028508SToomas Soome /*-
2*22028508SToomas Soome * Copyright (c) 1990, 1993
3*22028508SToomas Soome * The Regents of the University of California. All rights reserved.
4*22028508SToomas Soome *
5*22028508SToomas Soome * Redistribution and use in source and binary forms, with or without
6*22028508SToomas Soome * modification, are permitted provided that the following conditions
7*22028508SToomas Soome * are met:
8*22028508SToomas Soome * 1. Redistributions of source code must retain the above copyright
9*22028508SToomas Soome * notice, this list of conditions and the following disclaimer.
10*22028508SToomas Soome * 2. Redistributions in binary form must reproduce the above copyright
11*22028508SToomas Soome * notice, this list of conditions and the following disclaimer in the
12*22028508SToomas Soome * documentation and/or other materials provided with the distribution.
13*22028508SToomas Soome * 3. Neither the name of the University nor the names of its contributors
14*22028508SToomas Soome * may be used to endorse or promote products derived from this software
15*22028508SToomas Soome * without specific prior written permission.
16*22028508SToomas Soome *
17*22028508SToomas Soome * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18*22028508SToomas Soome * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19*22028508SToomas Soome * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20*22028508SToomas Soome * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21*22028508SToomas Soome * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22*22028508SToomas Soome * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23*22028508SToomas Soome * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24*22028508SToomas Soome * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25*22028508SToomas Soome * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26*22028508SToomas Soome * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*22028508SToomas Soome * SUCH DAMAGE.
28*22028508SToomas Soome */
29*22028508SToomas Soome
30*22028508SToomas Soome #if defined(LIBC_SCCS) && !defined(lint)
31*22028508SToomas Soome static char sccsid[] = "@(#)ffs.c 8.1 (Berkeley) 6/4/93";
32*22028508SToomas Soome #endif /* LIBC_SCCS and not lint */
33*22028508SToomas Soome #include <sys/cdefs.h>
34*22028508SToomas Soome __FBSDID("$FreeBSD$");
35*22028508SToomas Soome
36*22028508SToomas Soome #include <strings.h>
37*22028508SToomas Soome
38*22028508SToomas Soome /*
39*22028508SToomas Soome * Find First Set bit
40*22028508SToomas Soome */
41*22028508SToomas Soome int
ffs(int mask)42*22028508SToomas Soome ffs(int mask)
43*22028508SToomas Soome {
44*22028508SToomas Soome int bit;
45*22028508SToomas Soome
46*22028508SToomas Soome if (mask == 0)
47*22028508SToomas Soome return(0);
48*22028508SToomas Soome for (bit = 1; !(mask & 1); bit++)
49*22028508SToomas Soome mask = (unsigned int)mask >> 1;
50*22028508SToomas Soome return (bit);
51*22028508SToomas Soome }
52