1/* Test mpfr_get_ld_2exp.
2
3Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4Contributed by the Arenaire and Cacao projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7Contributed by Damien Stehle.
8
9The GNU MPFR Library is free software; you can redistribute it and/or modify
10it under the terms of the GNU Lesser General Public License as published by
11the Free Software Foundation; either version 3 of the License, or (at your
12option) any later version.
13
14The GNU MPFR Library is distributed in the hope that it will be useful, but
15WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
17License for more details.
18
19You should have received a copy of the GNU Lesser General Public License
20along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
21http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2251 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
23
24#include <stdio.h>
25#include <stdlib.h>
26#include <float.h>
27
28#include "mpfr-test.h"
29
30/* Check that hardware rounding doesn't make mpfr_get_ld_2exp return a value
31   outside its defined range. */
32static void
33check_round (void)
34{
35  static const unsigned long data[] = {1, 32, 53, 54, 63, 64, 65, 127, 128, 256, 512 };
36  mpfr_t  f;
37  long double  got;
38  long    got_exp;
39  int     i, rnd_mode, neg;
40
41  mpfr_init2 (f, 1024L);
42
43  for (rnd_mode = 0; rnd_mode < MPFR_RND_MAX ; rnd_mode++)
44    {
45      for (i = 0; i < (int) numberof (data); i++)
46        {
47          mpfr_set_ui (f, 1L, MPFR_RNDZ);
48          mpfr_mul_2exp (f, f, data[i], MPFR_RNDZ);
49          mpfr_sub_ui (f, f, 1L, MPFR_RNDZ);
50
51          for (neg = 0; neg <= 1; neg++)
52            {
53              got = mpfr_get_ld_2exp (&got_exp, f, (mpfr_rnd_t) rnd_mode);
54
55              if (neg == 0
56                  ? (got < 0.5 || got >= 1.0)
57                  : (got <= -1.0 || got > -0.5))
58                {
59                  printf  ("mpfr_get_ld_2exp wrong on 2**%lu-1\n", data[i]);
60                  printf  ("result out of range, expect 0.5 <= got < 1.0\n");
61                  printf  ("   rnd_mode = %d\n", rnd_mode);
62                  printf  ("   data[i]  = %lu\n", data[i]);
63                  printf  ("   f    ");
64                  mpfr_out_str (stdout, 2, 0, f, MPFR_RNDN);
65                  printf  ("\n");
66                  d_trace ("   got  ", got);
67                  printf  ("   got exp  %ld\n", got_exp);
68                  exit(1);
69                }
70
71              mpfr_neg (f, f, MPFR_RNDZ);
72            }
73        }
74    }
75
76  mpfr_clear (f);
77}
78
79
80static void
81check_inf_nan (void)
82{
83  /* only if nans and infs are available */
84#if _GMP_IEEE_FLOATS
85  mpfr_t  x;
86  double  d;
87  long    exp;
88
89  mpfr_init2 (x, 123);
90
91  mpfr_set_inf (x, 1);
92  d = (double) mpfr_get_ld_2exp (&exp, x, MPFR_RNDZ);
93  ASSERT_ALWAYS (d > 0);
94  ASSERT_ALWAYS (DOUBLE_ISINF (d));
95
96  mpfr_set_inf (x, -1);
97  d = (double) mpfr_get_ld_2exp (&exp, x, MPFR_RNDZ);
98  ASSERT_ALWAYS (d < 0);
99  ASSERT_ALWAYS (DOUBLE_ISINF (d));
100
101  mpfr_set_nan (x);
102  d = (double) mpfr_get_ld_2exp (&exp, x, MPFR_RNDZ);
103  ASSERT_ALWAYS (DOUBLE_ISNAN (d));
104
105  mpfr_clear (x);
106#endif
107}
108
109static void
110bug20090520 (void)
111{
112  mpfr_t x;
113  long double d, e;
114  int i;
115
116  mpfr_init (x);
117  mpfr_set_ui (x, 1, MPFR_RNDN);
118  d = 1.0;
119  mpfr_div_2exp (x, x, 16383, MPFR_RNDN);
120  for (i = 0; i < 16383; i++)
121    d *= 0.5;
122  e = mpfr_get_ld (x, MPFR_RNDN);
123  if (e != d)
124    {
125      printf ("mpfr_get_ld(1e-16383) failed\n");
126      printf ("expected %.20Le\n", d);
127      printf ("got      %.20Le\n", e);
128      exit (1);
129    }
130  mpfr_clear (x);
131}
132
133int
134main (void)
135{
136  tests_start_mpfr ();
137  mpfr_test_init ();
138
139  bug20090520 ();
140
141  check_round ();
142  check_inf_nan ();
143
144  tests_end_mpfr ();
145  return 0;
146}
147