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 #pragma weak isnan = __isnan
30 #pragma weak _isnan = __isnan
31 #pragma weak _isnand = __isnan
32 #pragma weak isnand = __isnan
33
34 #include "libm.h"
35
36 /*
37 * The following implementation assumes fast 64-bit integer arith-
38 * metic. This is fine for sparc because we build libm in v8plus
39 * mode. It's also fine for sparcv9 and amd64. For x86, it would
40 * be better to use 32-bit code, but we have assembly for x86.
41 */
42 int
__isnan(double x)43 __isnan(double x) {
44 long long llx;
45
46 llx = *(long long *)&x & ~0x8000000000000000ull;
47 return ((unsigned long long)(0x7ff0000000000000ll - llx) >> 63);
48 }
49