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
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
/* Test of splitting a 'long double' into fraction and mantissa.
Copyright (C) 2007-2010 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU 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>
#include <math.h>
#include "signature.h"
SIGNATURE_CHECK (frexpl, long double, (long double, int *));
#include <float.h>
#include "fpucw.h"
#include "isnanl-nolibm.h"
#include "nan.h"
#include "macros.h"
/* Avoid some warnings from "gcc -Wshadow".
This file doesn't use the exp() function. */
#undef exp
#define exp exponent
/* On MIPS IRIX machines, LDBL_MIN_EXP is -1021, but the smallest reliable
exponent for 'long double' is -964. Similarly, on PowerPC machines,
LDBL_MIN_EXP is -1021, but the smallest reliable exponent for 'long double'
is -968. For exponents below that, the precision may be truncated to the
precision used for 'double'. */
#ifdef __sgi
# define MIN_NORMAL_EXP (LDBL_MIN_EXP + 57)
#elif defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__
# define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53)
#else
# define MIN_NORMAL_EXP LDBL_MIN_EXP
#endif
/* On HP-UX 10.20, negating 0.0L does not yield -0.0L.
So we use minus_zero instead.
IRIX cc can't put -0.0L into .data, but can compute at runtime.
Note that the expression -LDBL_MIN * LDBL_MIN does not work on other
platforms, such as when cross-compiling to PowerPC on MacOS X 10.5. */
#if defined __hpux || defined __sgi
static long double
compute_minus_zero (void)
{
return -LDBL_MIN * LDBL_MIN;
}
# define minus_zero compute_minus_zero ()
#else
long double minus_zero = -0.0L;
#endif
static long double
my_ldexp (long double x, int d)
{
for (; d > 0; d--)
x *= 2.0L;
for (; d < 0; d++)
x *= 0.5L;
return x;
}
int
main ()
{
int i;
long double x;
DECL_LONG_DOUBLE_ROUNDING
BEGIN_LONG_DOUBLE_ROUNDING ();
{ /* NaN. */
int exp = -9999;
long double mantissa;
x = NaNl ();
mantissa = frexpl (x, &exp);
ASSERT (isnanl (mantissa));
}
{ /* Positive infinity. */
int exp = -9999;
long double mantissa;
x = 1.0L / 0.0L;
mantissa = frexpl (x, &exp);
ASSERT (mantissa == x);
}
{ /* Negative infinity. */
int exp = -9999;
long double mantissa;
x = -1.0L / 0.0L;
mantissa = frexpl (x, &exp);
ASSERT (mantissa == x);
}
{ /* Positive zero. */
int exp = -9999;
long double mantissa;
x = 0.0L;
mantissa = frexpl (x, &exp);
ASSERT (exp == 0);
ASSERT (mantissa == x);
ASSERT (!signbit (mantissa));
}
{ /* Negative zero. */
int exp = -9999;
long double mantissa;
x = minus_zero;
mantissa = frexpl (x, &exp);
ASSERT (exp == 0);
ASSERT (mantissa == x);
ASSERT (signbit (mantissa));
}
for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.5L);
}
for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.5L);
}
for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.5L);
}
for (i = 1, x = -1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == -0.5L);
}
for (i = 1, x = -1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == -0.5L);
}
for (; i >= LDBL_MIN_EXP - 100 && x < 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == -0.5L);
}
for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.505L);
}
for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.505L);
}
for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa >= 0.5L);
ASSERT (mantissa < 1.0L);
ASSERT (mantissa == my_ldexp (x, - exp));
}
for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.866025L);
}
for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i);
ASSERT (mantissa == 0.866025L);
}
for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = frexpl (x, &exp);
ASSERT (exp == i || exp == i + 1);
ASSERT (mantissa >= 0.5L);
ASSERT (mantissa < 1.0L);
ASSERT (mantissa == my_ldexp (x, - exp));
}
return 0;
}
|