1/* Test mpf_get_d_2exp.
2
3Copyright 2002, 2003, 2017, 2020 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library test suite.
6
7The GNU MP Library test suite is free software; you can redistribute it
8and/or modify it under the terms of the GNU General Public License as
9published by the Free Software Foundation; either version 3 of the License,
10or (at your option) any later version.
11
12The GNU MP Library test suite is distributed in the hope that it will be
13useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
15Public License for more details.
16
17You should have received a copy of the GNU General Public License along with
18the 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
26static void
27check_data (void)
28{
29  mpf_t   f;
30  double  got, want;
31  long    got_exp;
32  long    exp;
33  struct {
34    int base;
35    int shift;
36  } data[] = {
37   {-1, 1}, {-3, 2}, {-5, 3}, {-7, 3}, { 1, 1}, { 3, 2}, { 5, 3}, { 7, 3}
38  };
39
40  mpf_init2 (f, 3);
41
42  got = mpf_get_d_2exp (&got_exp, f);
43  if (got != 0 || got_exp != 0)
44    {
45      printf    ("mpf_get_d_2exp wrong on zero\n");
46      mpf_trace ("   f    ", f);
47      d_trace   ("   got  ", got);
48      printf    ("   got exp  %ld\n", got_exp);
49      abort();
50    }
51
52  for (exp = -513; exp <= 513; exp++)
53    {
54      size_t i;
55      for (i = 0; i < numberof (data); i++)
56	{
57	  want = (double) data[i].base / (1 << data[i].shift);
58	  mpf_set_d (f, want);
59
60	  if (exp >= 0)
61	    mpf_mul_2exp (f, f, exp);
62	  else
63	    mpf_div_2exp (f, f, -exp);
64
65	  got = mpf_get_d_2exp (&got_exp, f);
66	  if (got != want || got_exp != exp)
67	    {
68	      printf    ("mpf_get_d_2exp wrong on 2**%ld\n", exp);
69	      mpf_trace ("   f    ", f);
70	      d_trace   ("   want ", want);
71	      d_trace   ("   got  ", got);
72	      printf    ("   want exp %ld\n", exp);
73	      printf    ("   got exp  %ld\n", got_exp);
74	      abort();
75	    }
76	}
77    }
78  mpf_clear (f);
79}
80
81/* Check that hardware rounding doesn't make mpf_get_d_2exp return a value
82   outside its defined range. */
83static void
84check_round (void)
85{
86  static const unsigned long data[] = { 1, 32, 53, 54, 64, 128, 256, 512 };
87  mpf_t   f;
88  double  got;
89  long    got_exp;
90  int     i, rnd_mode, old_rnd_mode;
91
92  mpf_init2 (f, 1024L);
93  old_rnd_mode = tests_hardware_getround ();
94
95  for (rnd_mode = 0; rnd_mode < 4; rnd_mode++)
96    {
97      tests_hardware_setround (rnd_mode);
98
99      for (i = 0; i < numberof (data); i++)
100        {
101          mpf_set_ui (f, 1L);
102          mpf_mul_2exp (f, f, data[i]);
103          mpf_sub_ui (f, f, 1L);
104
105          got = mpf_get_d_2exp (&got_exp, f);
106          if (got < 0.5 || got >= 1.0)
107            {
108              printf    ("mpf_get_d_2exp bad on 2**%lu-1\n", data[i]);
109              printf    ("result out of range, expect 0.5 <= got < 1.0\n");
110              printf    ("   rnd_mode = %d\n", rnd_mode);
111              printf    ("   data[i]  = %lu\n", data[i]);
112              mpf_trace ("   f    ", f);
113              d_trace   ("   got  ", got);
114              printf    ("   got exp  %ld\n", got_exp);
115              abort();
116            }
117        }
118    }
119
120  mpf_clear (f);
121  tests_hardware_setround (old_rnd_mode);
122}
123
124
125int
126main (void)
127{
128  tests_start ();
129  mp_trace_base = 16;
130
131  check_data ();
132  check_round ();
133
134  tests_end ();
135  exit (0);
136}
137