summary refs log tree commit diff
path: root/stdlib/gen-tst-strtod-round.c
blob: 94d6afeaefac26af86beb43781e3a2a43db81556 (plain) (blame)
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
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
/* Generate table of tests in tst-strtod-round.c from
   tst-strtod-round-data.
   Copyright (C) 2012-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* Compile this program as:

   gcc -std=gnu11 -O2 -Wall -Wextra gen-tst-strtod-round.c -lmpfr \
     -o gen-tst-strtod-round

   (use of current MPFR version recommended) and run it as:

   gen-tst-strtod-round tst-strtod-round-data tst-strtod-round-data.h

   The output file will be generated as tst-strtod-round-data.h
*/


#define _GNU_SOURCE
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mpfr.h>

/* Work around incorrect ternary value from mpfr_strtofr
   <https://sympa.inria.fr/sympa/arc/mpfr/2012-08/msg00005.html>.  */
#define WORKAROUND

static int
string_to_fp (mpfr_t f, const char *s, mpfr_rnd_t rnd)
{
  mpfr_clear_overflow ();
#ifdef WORKAROUND
  mpfr_t f2;
  mpfr_init2 (f2, 100000);
  int r0 = mpfr_strtofr (f2, s, NULL, 0, rnd);
  int r = mpfr_set (f, f2, rnd);
  r |= mpfr_subnormalize (f, r, rnd);
  mpfr_clear (f2);
  return r0 | r;
#else
  int r = mpfr_strtofr (f, s, NULL, 0, rnd);
  r |= mpfr_subnormalize (f, r, rnd);
  return r;
#endif
}

void
print_fp (FILE *fout, mpfr_t f, const char *suffix)
{
  if (mpfr_inf_p (f))
    mpfr_fprintf (fout, "\t%sINF%s", mpfr_signbit (f) ? "-" : "", suffix);
  else
    mpfr_fprintf (fout, "\t%Ra%s", f, suffix);
}

static void
round_str (FILE *fout, const char *s, int prec, int emin, int emax,
	   bool ibm_ld)
{
  mpfr_t max_value;
  mpfr_t f;
  mpfr_set_default_prec (prec);
  mpfr_set_emin (emin);
  mpfr_set_emax (emax);
  mpfr_init (f);
  int r = string_to_fp (f, s, MPFR_RNDD);
  bool overflow = mpfr_overflow_p () != 0;
  if (ibm_ld)
    {
      assert (prec == 106 && emin == -1073 && emax == 1024);
      /* The maximum value in IBM long double has discontiguous
	 mantissa bits.  */
      mpfr_init2 (max_value, 107);
      mpfr_set_str (max_value, "0x1.fffffffffffff7ffffffffffffcp+1023", 0,
		    MPFR_RNDN);
      if (mpfr_cmpabs (f, max_value) > 0)
	{
	  r = 1;
	  overflow = true;
	}
    }
  mpfr_fprintf (fout, "\t%s,\n", r ? "false" : "true");
  print_fp (fout, f, overflow ? ", true,\n" : ", false,\n");
  string_to_fp (f, s, MPFR_RNDN);
  overflow = (mpfr_overflow_p () != 0
	      || (ibm_ld && mpfr_cmpabs (f, max_value) > 0));
  print_fp (fout, f, overflow ? ", true,\n" : ", false,\n");
  string_to_fp (f, s, MPFR_RNDZ);
  overflow = (mpfr_overflow_p () != 0
	      || (ibm_ld && mpfr_cmpabs (f, max_value) > 0));
  print_fp (fout, f, overflow ? ", true,\n" : ", false,\n");
  string_to_fp (f, s, MPFR_RNDU);
  overflow = (mpfr_overflow_p () != 0
	      || (ibm_ld && mpfr_cmpabs (f, max_value) > 0));
  print_fp (fout, f, overflow ? ", true" : ", false");
  mpfr_clear (f);
  if (ibm_ld)
    mpfr_clear (max_value);
}

static void
round_for_all (FILE *fout, const char *s)
{
  static const struct fmt {
    int prec;
    int emin;
    int emax;
    bool ibm_ld;
  } formats[] = {
    { 24, -148, 128, false },
    { 53, -1073, 1024, false },
    /* This is the Intel extended float format.  */
    { 64, -16444, 16384, false },
    /* This is the Motorola extended float format.  */
    { 64, -16445, 16384, false },
    { 106, -1073, 1024, true },
    { 113, -16493, 16384, false },
  };
  mpfr_fprintf (fout, "  TEST (\"");
  const char *p;
  for (p = s; *p; p++)
    {
      fputc (*p, fout);
      if ((p - s) % 60 == 59 && p[1])
	mpfr_fprintf (fout, "\"\n\t\"");
    }
  mpfr_fprintf (fout, "\",\n");
  int i;
  int n_formats = sizeof (formats) / sizeof (formats[0]);
  for (i = 0; i < n_formats; i++)
    {
      round_str (fout, s, formats[i].prec, formats[i].emin,
		 formats[i].emax, formats[i].ibm_ld);
      if (i < n_formats - 1)
	mpfr_fprintf (fout, ",\n");
    }
  mpfr_fprintf (fout, "),\n");
}

int
main (int argc, char **argv)
{
  char *p = NULL;
  size_t len;
  ssize_t nbytes;
  FILE *fin, *fout;
  char *fin_name, *fout_name;

  if (argc < 3)
    {
      fprintf (stderr, "Usage: %s <input> <output>\n", basename (argv[0]));
      return EXIT_FAILURE;
    }

  fin_name = argv[1];
  fout_name = argv[2];

  fin = fopen (fin_name, "r");
  if (fin == NULL)
    {
      perror ("Could not open input for reading");
      return EXIT_FAILURE;
    }

  fout = fopen (fout_name, "w");
  if (fout == NULL)
    {
      perror ("Could not open output for writing");
      return EXIT_FAILURE;
    }

  fprintf (fout, "/* This file was generated by %s from %s.  */\n",
	  __FILE__, fin_name);
  fputs ("static const struct test tests[] = {\n", fout);
  while ((nbytes = getline (&p, &len, fin)) != -1)
    {
      if (p[nbytes - 1] == '\n')
	p[nbytes - 1] = 0;
      round_for_all (fout, p);
      free (p);
      p = NULL;
    }
  fputs ("};\n", fout);

  return EXIT_SUCCESS;
}