xref: /freebsd/lib/libc/gen/isnan.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
29 #include <math.h>
30 
31 #include "fpmath.h"
32 
33 /*
34  * XXX These routines belong in libm, but they must remain in libc for
35  *     binary compat until we can bump libm's major version number.
36  *
37  * Note this only applies to the dynamic versions of libm and libc, so
38  * for the static and profiled versions we stub out the definitions.
39  * Otherwise you cannot link statically to libm and libc at the same
40  * time, when calling both functions.
41  */
42 
43 #ifdef PIC
44 /*
45  * Because math.h defines __isnan and __isnanf as aliases for compatibility with
46  * glibc and CUDA, we have to undefine them here to avoid redefinition errors.
47  */
48 #undef __isnan
49 #undef __isnanf
50 
51 __weak_reference(__isnan, isnan);
52 __weak_reference(__isnanf, isnanf);
53 
54 int
55 __isnan(double d)
56 {
57 	union IEEEd2bits u;
58 
59 	u.d = d;
60 	return (u.bits.exp == 2047 && (u.bits.manl != 0 || u.bits.manh != 0));
61 }
62 
63 int
64 __isnanf(float f)
65 {
66 	union IEEEf2bits u;
67 
68 	u.f = f;
69 	return (u.bits.exp == 255 && u.bits.man != 0);
70 }
71 #endif /* PIC */
72