xref: /illumos-gate/usr/src/lib/libm/i386/src/isnan.s (revision ddc0e0b5)
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 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23 */
24/*
25 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
26 * Use is subject to license terms.
27 */
28
29        .file "isnan.s"
30
31#include "libm.h"
32LIBM_ANSI_PRAGMA_WEAK(isnan,function)
33	.weak _isnan
34	.type _isnan,@function
35_isnan	= __isnan
36	.weak _isnand
37	.type _isnand,@function
38_isnand	= __isnan
39	.weak isnand
40	.type isnand,@function
41isnand	= __isnan
42
43	ENTRY(isnan)
44	movl    8(%esp),%eax		/ eax <-- hi_32(x)
45	andl    $0x7fffffff,%eax	/ eax <-- hi_32(abs(x))
46	subl    $0x7ff00000,%eax	/ weed out finite values
47	jae	.nan_or_inf		/ no jump if arg. is finite
48	movl	$0,%eax			/ ansi needs (eax) = 0
49	ret
50.nan_or_inf:
51	ja	.got_nan		/ no jump if arg. may be infinite;
52					/ let nan waste time
53					/ (eax) = 0 here
54	testl	$0xffffffff,4(%esp)	/ ZF <-- 1 iff lo_frac. = 0
55					/	   iff arg. is infinite
56	jnz	.got_nan		/ no jump if arg. is infinite;
57	ret
58.got_nan:
59	movl	$1,%eax			/ %eax was 0, must be made 1 to
60					/ indicate TRUE
61	ret
62	.align	4
63	SET_SIZE(isnan)
64