1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
/* Test for NaN that does not need libm.
Copyright (C) 2007-2016 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
#include <config.h>
/* Specification. */
#ifdef USE_LONG_DOUBLE
/* Specification found in math.h or isnanl-nolibm.h. */
extern int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
#elif ! defined USE_FLOAT
/* Specification found in math.h or isnand-nolibm.h. */
extern int rpl_isnand (double x);
#else /* defined USE_FLOAT */
/* Specification found in math.h or isnanf-nolibm.h. */
extern int rpl_isnanf (float x);
#endif
#include <float.h>
#include <string.h>
#include "float+.h"
#ifdef USE_LONG_DOUBLE
# define FUNC rpl_isnanl
# define DOUBLE long double
# define MAX_EXP LDBL_MAX_EXP
# define MIN_EXP LDBL_MIN_EXP
# if defined LDBL_EXPBIT0_WORD && defined LDBL_EXPBIT0_BIT
# define KNOWN_EXPBIT0_LOCATION
# define EXPBIT0_WORD LDBL_EXPBIT0_WORD
# define EXPBIT0_BIT LDBL_EXPBIT0_BIT
# endif
# define SIZE SIZEOF_LDBL
# define L_(literal) literal##L
#elif ! defined USE_FLOAT
# define FUNC rpl_isnand
# define DOUBLE double
# define MAX_EXP DBL_MAX_EXP
# define MIN_EXP DBL_MIN_EXP
# if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
# define KNOWN_EXPBIT0_LOCATION
# define EXPBIT0_WORD DBL_EXPBIT0_WORD
# define EXPBIT0_BIT DBL_EXPBIT0_BIT
# endif
# define SIZE SIZEOF_DBL
# define L_(literal) literal
#else /* defined USE_FLOAT */
# define FUNC rpl_isnanf
# define DOUBLE float
# define MAX_EXP FLT_MAX_EXP
# define MIN_EXP FLT_MIN_EXP
# if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
# define KNOWN_EXPBIT0_LOCATION
# define EXPBIT0_WORD FLT_EXPBIT0_WORD
# define EXPBIT0_BIT FLT_EXPBIT0_BIT
# endif
# define SIZE SIZEOF_FLT
# define L_(literal) literal##f
#endif
#define EXP_MASK ((MAX_EXP - MIN_EXP) | 7)
#define NWORDS \
((sizeof (DOUBLE) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
typedef union { DOUBLE value; unsigned int word[NWORDS]; } memory_double;
/* Most hosts nowadays use IEEE floating point, so they use IEC 60559
representations, have infinities and NaNs, and do not trap on
exceptions. Define IEEE_FLOATING_POINT if this host is one of the
typical ones. The C11 macro __STDC_IEC_559__ is close to what is
wanted here, but is not quite right because this file does not require
all the features of C11 Annex F (and does not require C11 at all,
for that matter). */
#define IEEE_FLOATING_POINT (FLT_RADIX == 2 && FLT_MANT_DIG == 24 \
&& FLT_MIN_EXP == -125 && FLT_MAX_EXP == 128)
int
FUNC (DOUBLE x)
{
#if defined KNOWN_EXPBIT0_LOCATION && IEEE_FLOATING_POINT
# if defined USE_LONG_DOUBLE && ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
/* Special CPU dependent code is needed to treat bit patterns outside the
IEEE 754 specification (such as Pseudo-NaNs, Pseudo-Infinities,
Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals) as NaNs.
These bit patterns are:
- exponent = 0x0001..0x7FFF, mantissa bit 63 = 0,
- exponent = 0x0000, mantissa bit 63 = 1.
The NaN bit pattern is:
- exponent = 0x7FFF, mantissa >= 0x8000000000000001. */
memory_double m;
unsigned int exponent;
m.value = x;
exponent = (m.word[EXPBIT0_WORD] >> EXPBIT0_BIT) & EXP_MASK;
# ifdef WORDS_BIGENDIAN
/* Big endian: EXPBIT0_WORD = 0, EXPBIT0_BIT = 16. */
if (exponent == 0)
return 1 & (m.word[0] >> 15);
else if (exponent == EXP_MASK)
return (((m.word[0] ^ 0x8000U) << 16) | m.word[1] | (m.word[2] >> 16)) != 0;
else
return 1 & ~(m.word[0] >> 15);
# else
/* Little endian: EXPBIT0_WORD = 2, EXPBIT0_BIT = 0. */
if (exponent == 0)
return (m.word[1] >> 31);
else if (exponent == EXP_MASK)
return ((m.word[1] ^ 0x80000000U) | m.word[0]) != 0;
else
return (m.word[1] >> 31) ^ 1;
# endif
# else
/* Be careful to not do any floating-point operation on x, such as x == x,
because x may be a signaling NaN. */
# if defined __SUNPRO_C || defined __ICC || defined _MSC_VER \
|| defined __DECC || defined __TINYC__ \
|| (defined __sgi && !defined __GNUC__)
/* The Sun C 5.0, Intel ICC 10.0, Microsoft Visual C/C++ 9.0, Compaq (ex-DEC)
6.4, and TinyCC compilers don't recognize the initializers as constant
expressions. The Compaq compiler also fails when constant-folding
0.0 / 0.0 even when constant-folding is not required. The Microsoft
Visual C/C++ compiler also fails when constant-folding 1.0 / 0.0 even
when constant-folding is not required. The SGI MIPSpro C compiler
complains about "floating-point operation result is out of range". */
static DOUBLE zero = L_(0.0);
memory_double nan;
DOUBLE plus_inf = L_(1.0) / zero;
DOUBLE minus_inf = -L_(1.0) / zero;
nan.value = zero / zero;
# else
static memory_double nan = { L_(0.0) / L_(0.0) };
static DOUBLE plus_inf = L_(1.0) / L_(0.0);
static DOUBLE minus_inf = -L_(1.0) / L_(0.0);
# endif
{
memory_double m;
/* A NaN can be recognized through its exponent. But exclude +Infinity and
-Infinity, which have the same exponent. */
m.value = x;
if (((m.word[EXPBIT0_WORD] ^ nan.word[EXPBIT0_WORD])
& (EXP_MASK << EXPBIT0_BIT))
== 0)
return (memcmp (&m.value, &plus_inf, SIZE) != 0
&& memcmp (&m.value, &minus_inf, SIZE) != 0);
else
return 0;
}
# endif
#else
/* The configuration did not find sufficient information, or does
not use IEEE floating point. Give up about the signaling NaNs;
handle only the quiet NaNs. */
if (x == x)
{
# if defined USE_LONG_DOUBLE && ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
/* Detect any special bit patterns that pass ==; see comment above. */
memory_double m1;
memory_double m2;
memset (&m1.value, 0, SIZE);
memset (&m2.value, 0, SIZE);
m1.value = x;
m2.value = x + (x ? 0.0L : -0.0L);
if (memcmp (&m1.value, &m2.value, SIZE) != 0)
return 1;
# endif
return 0;
}
else
return 1;
#endif
}
|
