1 /* Return 1 if argument is a NaN, else 0.
2 Copyright (C) 2007-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19 /* Ugly kludge to avoid declarations. */
20 #define __isnanf not___isnanf
21 #define isnanf not_isnanf
22 #define __GI___isnanf not__GI___isnanf
23
24 #include <math.h>
25 #include <math_private.h>
26 #include <math_ldbl_opt.h>
27
28 #undef __isnanf
29 #undef isnanf
30 #undef __GI___isnanf
31
32 int
__isnan(double x)33 __isnan (double x)
34 {
35 uint64_t ix;
36 EXTRACT_WORDS64 (ix, x);
37 return ix * 2 > 0xffe0000000000000ul;
38 }
39
40 hidden_def (__isnan)
41 weak_alias (__isnan, isnan)
42
43 /* It turns out that the 'double' version will also always work for
44 single-precision. */
45 strong_alias (__isnan, __isnanf)
46 weak_alias (__isnan, isnanf)
47
48 /* ??? GCC 4.8 fails to look through chains of aliases with asm names
49 attached. Work around this for now. */
50 hidden_ver (__isnan, __isnanf)
51
52 #ifdef NO_LONG_DOUBLE
53 strong_alias (__isnan, __isnanl)
54 weak_alias (__isnan, isnanl)
55 #endif
56 #if LONG_DOUBLE_COMPAT(libc, GLIBC_2_0)
57 compat_symbol (libc, __isnan, __isnanl, GLIBC_2_0);
58 compat_symbol (libc, isnan, isnanl, GLIBC_2_0);
59 #endif
60