1 /* Test of splitting a 'long double' into fraction and mantissa.
2 Copyright (C) 2007-2021 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
18
19 #include <config.h>
20
21 #include "printf-frexpl.h"
22
23 #include <float.h>
24
25 #include "fpucw.h"
26 #include "macros.h"
27
28 /* On MIPS IRIX machines, LDBL_MIN_EXP is -1021, but the smallest reliable
29 exponent for 'long double' is -964. Similarly, on PowerPC machines,
30 LDBL_MIN_EXP is -1021, but the smallest reliable exponent for 'long double'
31 is -968. For exponents below that, the precision may be truncated to the
32 precision used for 'double'. */
33 #ifdef __sgi
34 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 57)
35 # define MIN_SUBNORMAL_EXP MIN_NORMAL_EXP
36 #elif defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__
37 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53)
38 # define MIN_SUBNORMAL_EXP MIN_NORMAL_EXP
39 #else
40 # define MIN_NORMAL_EXP LDBL_MIN_EXP
41 # define MIN_SUBNORMAL_EXP (LDBL_MIN_EXP - 100)
42 #endif
43
44 static long double
45 my_ldexp (long double x, int d)
46 {
47 for (; d > 0; d--)
48 x *= 2.0L;
49 for (; d < 0; d++)
50 x *= 0.5L;
51 return x;
52 }
53
54 int
55 main ()
56 {
57 int i;
58 long double x;
59 DECL_LONG_DOUBLE_ROUNDING
60
61 BEGIN_LONG_DOUBLE_ROUNDING ();
62
63 for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
64 {
65 int exp = -9999;
66 long double mantissa = printf_frexpl (x, &exp);
67 ASSERT (exp == i - 1);
68 ASSERT (mantissa == 1.0L);
69 }
70 for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
71 {
72 int exp = -9999;
73 long double mantissa = printf_frexpl (x, &exp);
74 ASSERT (exp == i - 1);
75 ASSERT (mantissa == 1.0L);
76 }
77 for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
78 {
79 int exp = -9999;
80 long double mantissa = printf_frexpl (x, &exp);
81 ASSERT (exp == LDBL_MIN_EXP - 1);
82 ASSERT (mantissa == my_ldexp (1.0L, i - LDBL_MIN_EXP));
83 }
84
85 for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
86 {
87 int exp = -9999;
88 long double mantissa = printf_frexpl (x, &exp);
89 ASSERT (exp == i - 1);
90 ASSERT (mantissa == 1.01L);
91 }
92 for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
93 {
94 int exp = -9999;
95 long double mantissa = printf_frexpl (x, &exp);
96 ASSERT (exp == i - 1);
97 ASSERT (mantissa == 1.01L);
98 }
99 for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
100 {
101 int exp = -9999;
102 long double mantissa = printf_frexpl (x, &exp);
103 ASSERT (exp == LDBL_MIN_EXP - 1);
104 ASSERT (mantissa >= my_ldexp (1.0L, i - LDBL_MIN_EXP));
105 ASSERT (mantissa <= my_ldexp (2.0L, i - LDBL_MIN_EXP));
106 ASSERT (mantissa == my_ldexp (x, - exp));
107 }
108
109 for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
110 {
111 int exp = -9999;
112 long double mantissa = printf_frexpl (x, &exp);
113 ASSERT (exp == i - 1);
114 ASSERT (mantissa == 1.73205L);
115 }
116 for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
117 {
118 int exp = -9999;
119 long double mantissa = printf_frexpl (x, &exp);
120 ASSERT (exp == i - 1);
121 ASSERT (mantissa == 1.73205L);
122 }
123 for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
124 {
125 int exp = -9999;
126 long double mantissa = printf_frexpl (x, &exp);
127 ASSERT (exp == LDBL_MIN_EXP - 1);
128 ASSERT (mantissa >= my_ldexp (1.0L, i - LDBL_MIN_EXP));
129 ASSERT (mantissa <= my_ldexp (2.0L, i - LDBL_MIN_EXP));
130 ASSERT (mantissa == my_ldexp (x, - exp));
131 }
132
133 return 0;
134 }