xref: /titanic_41/usr/src/lib/libm/common/C/isnan.c (revision 5b2ba9d3d1e04dde804c89e9879f7dfc9bcebf61)
1*5b2ba9d3SPiotr Jasiukajtis /*
2*5b2ba9d3SPiotr Jasiukajtis  * CDDL HEADER START
3*5b2ba9d3SPiotr Jasiukajtis  *
4*5b2ba9d3SPiotr Jasiukajtis  * The contents of this file are subject to the terms of the
5*5b2ba9d3SPiotr Jasiukajtis  * Common Development and Distribution License (the "License").
6*5b2ba9d3SPiotr Jasiukajtis  * You may not use this file except in compliance with the License.
7*5b2ba9d3SPiotr Jasiukajtis  *
8*5b2ba9d3SPiotr Jasiukajtis  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5b2ba9d3SPiotr Jasiukajtis  * or http://www.opensolaris.org/os/licensing.
10*5b2ba9d3SPiotr Jasiukajtis  * See the License for the specific language governing permissions
11*5b2ba9d3SPiotr Jasiukajtis  * and limitations under the License.
12*5b2ba9d3SPiotr Jasiukajtis  *
13*5b2ba9d3SPiotr Jasiukajtis  * When distributing Covered Code, include this CDDL HEADER in each
14*5b2ba9d3SPiotr Jasiukajtis  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*5b2ba9d3SPiotr Jasiukajtis  * If applicable, add the following below this CDDL HEADER, with the
16*5b2ba9d3SPiotr Jasiukajtis  * fields enclosed by brackets "[]" replaced with your own identifying
17*5b2ba9d3SPiotr Jasiukajtis  * information: Portions Copyright [yyyy] [name of copyright owner]
18*5b2ba9d3SPiotr Jasiukajtis  *
19*5b2ba9d3SPiotr Jasiukajtis  * CDDL HEADER END
20*5b2ba9d3SPiotr Jasiukajtis  */
21*5b2ba9d3SPiotr Jasiukajtis /*
22*5b2ba9d3SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23*5b2ba9d3SPiotr Jasiukajtis  */
24*5b2ba9d3SPiotr Jasiukajtis /*
25*5b2ba9d3SPiotr Jasiukajtis  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
26*5b2ba9d3SPiotr Jasiukajtis  * Use is subject to license terms.
27*5b2ba9d3SPiotr Jasiukajtis  */
28*5b2ba9d3SPiotr Jasiukajtis 
29*5b2ba9d3SPiotr Jasiukajtis #pragma weak isnan = __isnan
30*5b2ba9d3SPiotr Jasiukajtis #pragma weak _isnan = __isnan
31*5b2ba9d3SPiotr Jasiukajtis #pragma weak _isnand = __isnan
32*5b2ba9d3SPiotr Jasiukajtis #pragma weak isnand = __isnan
33*5b2ba9d3SPiotr Jasiukajtis 
34*5b2ba9d3SPiotr Jasiukajtis #include "libm.h"
35*5b2ba9d3SPiotr Jasiukajtis 
36*5b2ba9d3SPiotr Jasiukajtis /*
37*5b2ba9d3SPiotr Jasiukajtis  * The following implementation assumes fast 64-bit integer arith-
38*5b2ba9d3SPiotr Jasiukajtis  * metic.  This is fine for sparc because we build libm in v8plus
39*5b2ba9d3SPiotr Jasiukajtis  * mode.  It's also fine for sparcv9 and amd64.  For x86, it would
40*5b2ba9d3SPiotr Jasiukajtis  * be better to use 32-bit code, but we have assembly for x86.
41*5b2ba9d3SPiotr Jasiukajtis  */
42*5b2ba9d3SPiotr Jasiukajtis int
__isnan(double x)43*5b2ba9d3SPiotr Jasiukajtis __isnan(double x) {
44*5b2ba9d3SPiotr Jasiukajtis 	long long	llx;
45*5b2ba9d3SPiotr Jasiukajtis 
46*5b2ba9d3SPiotr Jasiukajtis 	llx = *(long long *)&x & ~0x8000000000000000ull;
47*5b2ba9d3SPiotr Jasiukajtis 	return ((unsigned long long)(0x7ff0000000000000ll - llx) >> 63);
48*5b2ba9d3SPiotr Jasiukajtis }
49