1/*
2 * Copyright (c) 1993 Winning Strategies, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
--- 15 unchanged lines hidden (view full) ---
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD: head/lib/libc/i386/string/ffs.S 97748 2002-06-02 20:05:59Z schweikh $");
33
34/*
35 * ffs(value)
36 * finds the first bit set in value and returns the index of
37 * that bit. Bits are numbered starting from 1, starting at the
38 * rightmost bit. A return value of 0 means that the argument
39 * was zero.
40 *
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46 bsfl 4(%esp),%eax
47 jz L1 /* ZF is set if all bits are 0 */
48 incl %eax /* bits numbered from 1, not 0 */
49 ret
50
51 .align 2
52L1: xorl %eax,%eax /* clear result */
53 ret
2 * Copyright (c) 1993 Winning Strategies, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
--- 15 unchanged lines hidden (view full) ---
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD: head/lib/libc/i386/string/ffs.S 97748 2002-06-02 20:05:59Z schweikh $");
33
34/*
35 * ffs(value)
36 * finds the first bit set in value and returns the index of
37 * that bit. Bits are numbered starting from 1, starting at the
38 * rightmost bit. A return value of 0 means that the argument
39 * was zero.
40 *
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46 bsfl 4(%esp),%eax
47 jz L1 /* ZF is set if all bits are 0 */
48 incl %eax /* bits numbered from 1, not 0 */
49 ret
50
51 .align 2
52L1: xorl %eax,%eax /* clear result */
53 ret