1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29/*
30 * Common implementation of ffs for kernel, mdb, and libc.  Note that mdb
31 * renames ffs into mdb_ffs to avoid user-space clashes with the signature of
32 * ffs(3C).
33 */
34
35#if defined(_KERNEL) || defined(ffs)
36#include <sys/int_types.h>
37#define	arg_t	uintmax_t
38#else
39#define	arg_t	int
40#include "lint.h"
41#endif
42
43int
44ffs(arg_t bits)
45{
46	int i;
47
48	if (bits == 0)
49		return (0);
50	for (i = 1; ; i++, bits >>= 1) {
51		if (bits & 1)
52			break;
53	}
54	return (i);
55}
56