xref: /freebsd/lib/libc/gen/isnan.c (revision a0409676120c1e558d0ade943019934e0f15118d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <math.h>
32 
33 #include "fpmath.h"
34 
35 /*
36  * XXX These routines belong in libm, but they must remain in libc for
37  *     binary compat until we can bump libm's major version number.
38  *
39  * Note this only applies to the dynamic versions of libm and libc, so
40  * for the static and profiled versions we stub out the definitions.
41  * Otherwise you cannot link statically to libm and libc at the same
42  * time, when calling both functions.
43  */
44 
45 #ifdef PIC
46 /*
47  * Because math.h defines __isnan and __isnanf as aliases for compatibility with
48  * glibc and CUDA, we have to undefine them here to avoid redefinition errors.
49  */
50 #undef __isnan
51 #undef __isnanf
52 
53 __weak_reference(__isnan, isnan);
54 __weak_reference(__isnanf, isnanf);
55 
56 int
57 __isnan(double d)
58 {
59 	union IEEEd2bits u;
60 
61 	u.d = d;
62 	return (u.bits.exp == 2047 && (u.bits.manl != 0 || u.bits.manh != 0));
63 }
64 
65 int
66 __isnanf(float f)
67 {
68 	union IEEEf2bits u;
69 
70 	u.f = f;
71 	return (u.bits.exp == 255 && u.bits.man != 0);
72 }
73 #endif /* PIC */
74