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
|
/* Test of splitting a double into fraction and mantissa.
Copyright (C) 2007-2024 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 <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
#include <config.h>
#include "printf-frexp.h"
#include <float.h>
#include "macros.h"
static double
my_ldexp (double x, int d)
{
for (; d > 0; d--)
x *= 2.0;
for (; d < 0; d++)
x *= 0.5;
return x;
}
int
main ()
{
int i;
/* The use of 'volatile' guarantees that excess precision bits are dropped
when dealing with denormalized numbers. It is necessary on x86 systems
where double-floats are not IEEE compliant by default, to avoid that the
results become platform and compiler option dependent. 'volatile' is a
portable alternative to gcc's -ffloat-store option. */
volatile double x;
for (i = 1, x = 1.0; i <= DBL_MAX_EXP; i++, x *= 2.0)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.0);
}
for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.0);
}
for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == DBL_MIN_EXP - 1);
ASSERT (mantissa == my_ldexp (1.0, i - DBL_MIN_EXP));
}
for (i = 1, x = 1.01; i <= DBL_MAX_EXP; i++, x *= 2.0)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.01);
}
for (i = 1, x = 1.01; i >= DBL_MIN_EXP; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.01);
}
for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == DBL_MIN_EXP - 1);
ASSERT (mantissa >= my_ldexp (1.0, i - DBL_MIN_EXP));
ASSERT (mantissa <= my_ldexp (2.0, i - DBL_MIN_EXP));
ASSERT (mantissa == my_ldexp (x, - exp));
}
for (i = 1, x = 1.73205; i <= DBL_MAX_EXP; i++, x *= 2.0)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.73205);
}
for (i = 1, x = 1.73205; i >= DBL_MIN_EXP; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.73205);
}
for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
{
int exp = -9999;
double mantissa = printf_frexp (x, &exp);
ASSERT (exp == DBL_MIN_EXP - 1);
ASSERT (mantissa >= my_ldexp (1.0, i - DBL_MIN_EXP));
ASSERT (mantissa <= my_ldexp (2.0, i - DBL_MIN_EXP));
ASSERT (mantissa == my_ldexp (x, - exp));
}
return 0;
}
|
