1 /* Test mpz_set_d and mpz_init_set_d.
2
3 Copyright 2000-2003, 2006 Free Software Foundation, Inc.
4
5 This file is part of the GNU MP Library test suite.
6
7 The GNU MP Library test suite is free software; you can redistribute it
8 and/or modify it under the terms of the GNU General Public License as
9 published by the Free Software Foundation; either version 3 of the License,
10 or (at your option) any later version.
11
12 The GNU MP Library test suite is distributed in the hope that it will be
13 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 Public License for more details.
16
17 You should have received a copy of the GNU General Public License along with
18 the GNU MP Library test suite. If not, see https://www.gnu.org/licenses/. */
19
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include "gmp-impl.h"
23 #include "tests.h"
24
25
26 void
check_data(void)27 check_data (void)
28 {
29 static const struct {
30 double d;
31 mp_size_t want_size;
32 mp_limb_t want_data[2];
33 } data[] = {
34
35 { 0.0, 0 },
36 { 1.0, 1, { 1 } },
37 { -1.0, -1, { 1 } },
38
39 { 123.0, 1, { 123 } },
40 { -123.0, -1, { 123 } },
41
42 { 1e-1, 0, { 0 } },
43 { -1e-1, 0, { 0 } },
44 { 2.328306436538696e-10, 0, { 0 } },
45 { -2.328306436538696e-10, 0, { 0 } },
46 { 5.421010862427522e-20, 0, { 0 } },
47 { -5.421010862427522e-20, 0, { 0 } },
48 { 2.938735877055719e-39, 0, { 0 } },
49 { -2.938735877055719e-39, 0, { 0 } },
50 };
51
52 mpz_t z;
53 int i;
54
55 for (i = 0; i < numberof (data); i++)
56 {
57 mpz_init (z);
58 mpz_set_d (z, data[i].d);
59 MPZ_CHECK_FORMAT (z);
60 if (z->_mp_size != data[i].want_size
61 || refmpn_cmp_allowzero (z->_mp_d, data[i].want_data,
62 ABS (data[i].want_size)) != 0)
63 {
64 printf ("mpz_set_d wrong on data[%d]\n", i);
65 bad:
66 d_trace (" d ", data[i].d);
67 printf (" got size %ld\n", (long) z->_mp_size);
68 printf (" want size %ld\n", (long) data[i].want_size);
69 mpn_trace (" got z", z->_mp_d, z->_mp_size);
70 mpn_trace (" want z", data[i].want_data, data[i].want_size);
71 abort();
72 }
73 mpz_clear (z);
74
75 mpz_init_set_d (z, data[i].d);
76 MPZ_CHECK_FORMAT (z);
77 if (z->_mp_size != data[i].want_size
78 || refmpn_cmp_allowzero (z->_mp_d, data[i].want_data,
79 ABS (data[i].want_size)) != 0)
80 {
81 printf ("mpz_init_set_d wrong on data[%d]\n", i);
82 goto bad;
83 }
84 mpz_clear (z);
85 }
86 }
87
88 /* Try mpz_set_d on values 2^i+1, while such a value fits a double. */
89 void
check_2n_plus_1(void)90 check_2n_plus_1 (void)
91 {
92 volatile double p, d, diff;
93 mpz_t want, got;
94 int i;
95
96 mpz_init (want);
97 mpz_init (got);
98
99 p = 1.0;
100 mpz_set_ui (want, 2L); /* gives 3 on first step */
101
102 for (i = 1; i < 500; i++)
103 {
104 mpz_mul_2exp (want, want, 1L);
105 mpz_sub_ui (want, want, 1L); /* want = 2^i+1 */
106
107 p *= 2.0; /* p = 2^i */
108 d = p + 1.0;
109 diff = d - p;
110 if (diff != 1.0)
111 break; /* rounding occurred, stop now */
112
113 mpz_set_d (got, d);
114 MPZ_CHECK_FORMAT (got);
115 if (mpz_cmp (got, want) != 0)
116 {
117 printf ("mpz_set_d wrong on 2^%d+1\n", i);
118 d_trace (" d ", d);
119 mpz_trace (" got ", got);
120 mpz_trace (" want ", want);
121 abort ();
122 }
123 }
124
125 mpz_clear (want);
126 mpz_clear (got);
127 }
128
129 int
main(void)130 main (void)
131 {
132 tests_start ();
133
134 check_data ();
135 check_2n_plus_1 ();
136
137 tests_end ();
138 exit (0);
139 }
140