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
|
/*
(C) Copyright IBM Corp. 2009
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of IBM nor the names of its contributors may be
used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#include "math_config.h"
#if defined(_NEED_FLOAT_HUGE) && !defined(_HAVE_LONG_DOUBLE_MATH)
# if (LDBL_MANT_DIG == 53) /* 64-bit long double */
static const long double scale = 0x1p54;
union ldbl {
long double x;
struct {
# ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
__uint32_t fracl;
__uint32_t frach:20;
__uint32_t exp:11;
__uint32_t sign:1;
# endif
# ifdef __IEEE_BIG_ENDIAN
__uint32_t sign:1;
__uint32_t exp:11;
__uint32_t frach:20;
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN
# else /* ARMEL without __VFP_FP__ */
__uint32_t frach:20;
__uint32_t exp:11;
__uint32_t sign:1;
# endif
__uint32_t fracl;
# endif
} u32;
};
# elif (LDBL_MANT_DIG == 64) /* 80-bit long double */
static const double scale = 0x1p65;
union ldbl {
long double x;
struct {
# ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
__uint32_t fracl;
__uint32_t frach;
__uint32_t exp:15;
__uint32_t sign:1;
__uint32_t pad:16;
# endif
# ifdef __IEEE_BIG_ENDIAN
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN /* for m86k */
__uint32_t sign:1;
__uint32_t exp:15;
__uint32_t pad:16;
# else /* ARM FPA10 math copprocessor */
__uint32_t exp:15;
__uint32_t pad:16;
__uint32_t sign:1;
# endif
__uint32_t frach;
__uint32_t fracl;
# endif
} u32;
};
# elif (LDBL_MANT_DIG == 106) /* 128-bit double double */
static const long double scale = 0x1p107l;
#define EXP_EXTRA_BIAS 100
union ldbl {
long double x;
struct {
# ifdef __IEEE_LITTLE_ENDIAN
__uint32_t frachm;
__uint32_t frach:20;
__uint32_t exp:11;
__uint32_t sign:1;
__uint32_t fracl;
__uint32_t fraclm:20;
__uint32_t exp_extra:11;
__uint32_t sign_extra:1;
# endif
# ifdef __IEEE_BIG_ENDIAN
__uint32_t sign:1;
__uint32_t exp:11;
__uint32_t frach:20;
__uint32_t frachm;
__uint32_t sign_extra:1;
__uint32_t exp_extra:11;
__uint32_t fraclm:20;
__uint32_t fracl;
# endif
} u32;
};
# elif (LDBL_MANT_DIG == 113) /* 128-bit long double */
static const long double scale = 0x1p114l;
union ldbl {
long double x;
struct {
# ifdef __IEEE_LITTLE_ENDIAN
__uint32_t fracl;
__uint32_t fraclm;
__uint32_t frachm;
__uint32_t frach:16;
__uint32_t exp:15;
__uint32_t sign:1;
# endif
# ifdef __IEEE_BIG_ENDIAN
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN
__uint32_t sign:1;
__uint32_t exp:15;
__uint32_t frach:16;
# else /* ARMEL without __VFP_FP__ */
__uint32_t frach:16;
__uint32_t exp:15;
__uint32_t sign:1;
# endif
__uint32_t frachm;
__uint32_t fraclm;
__uint32_t fracl;
# endif
} u32;
};
# else
# error Unsupported long double format.
# endif
static const int scale_exp = LDBL_MANT_DIG + 1;
long double
frexpl (long double x, int *eptr)
{
union ldbl u;
u.x = x;
int e = u.u32.exp;
*eptr = 0;
if (e == (LDBL_MAX_EXP*2 - 1) || x == 0)
return x; /* inf,nan,0 */
if (e == 0) /* subnormal */
{
u.x *= (long double) scale;
e = u.u32.exp;
*eptr -= scale_exp;
}
*eptr += e - (LDBL_MAX_EXP - 2);
u.u32.exp = LDBL_MAX_EXP - 2; /* -1 */
#ifdef EXP_EXTRA_BIAS
if (u.u32.exp_extra != 0)
u.u32.exp_extra = u.u32.exp - EXP_EXTRA_BIAS;
#endif
return u.x;
}
#endif /* _NEED_FLOAT_HUGE */
|
