xref: /titanic_44/usr/src/lib/libbc/libc/gen/common/sparc/ffs.s (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
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, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 1992 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27!	.seg	"data"
28!	.asciz ident	"%Z%%M%	%I%	%E% SMI"
29	.seg	".text"
30
31	.file	"ffs.s"
32
33#include <sun4/asm_linkage.h>
34
35	ENTRY(ffs)
36	tst	%o0		! if zero, done
37	bz	2f
38	clr	%o1		! delay slot, return zero if no bit set
391:
40	inc	%o1		! bit that will get checked
41	btst	1, %o0
42	be	1b		! if bit is zero, keep checking
43	srl	%o0, 1, %o0	! shift input right until we hit a 1 bit
442:
45	retl
46	mov	%o1, %o0	! return value is in o1
47	SET_SIZE(ffs)
48