1/* Test file for mpfr_{mul,div}_2{ui,si}.
2
3Copyright 1999, 2001-2004, 2006-2023 Free Software Foundation, Inc.
4Contributed by the AriC and Caramba projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#include "mpfr-test.h"
24
25static const char * const val[] = {
26  "1.0001@100","4.0004000000000@102", "4.0004000000000@97",
27  "1.ABF012345@-100","6.afc048d140000@-98","6.afc048d140000@-103",
28  "F.FFFFFFFFF@10000","3.fffffffffc000@10003","3.fffffffffc000@9998",
29  "1.23456789ABCDEF@42","4.8d159e26af37c@44","4.8d159e26af37c@39",
30  "17@42","5.c000000000000@45","5.c000000000000@40",
31  "42@-17","1.0800000000000@-13","1.0800000000000@-18"
32};
33
34static int
35test_mul (int i, int div, mpfr_ptr y, mpfr_srcptr x,
36          unsigned long int n, mpfr_rnd_t r)
37{
38  return
39    i == 0 ? (div ? mpfr_div_2ui : mpfr_mul_2ui) (y, x, n, r) :
40    i == 1 ? (div ? mpfr_div_2si : mpfr_mul_2si) (y, x, n, r) :
41    i == 2 ? (div ? mpfr_mul_2si : mpfr_div_2si) (y, x, -n, r) :
42    (exit (1), 0);
43}
44
45static void
46underflow (mpfr_exp_t e)
47{
48  mpfr_t x, y, z1, z2;
49  mpfr_exp_t emin;
50  int i, k, s;
51  int prec;
52  int rnd;
53  int div;
54  int inex1, inex2;
55  unsigned int flags1, flags2;
56
57  /* Test mul_2si(x, e - k), div_2si(x, k - e) and div_2ui(x, k - e) with
58   * emin = e, x = s * (1 + i/16), i in { -1, 0, 1 }, s in { -1, 1 }, and
59   * k = 1 to 4, by comparing the result with the one of a simple division.
60   */
61  emin = mpfr_get_emin ();
62  set_emin (e);
63  mpfr_inits2 (8, x, y, (mpfr_ptr) 0);
64  for (i = 15; i <= 17; i++)
65    for (s = 1; s >= -1; s -= 2)
66      {
67        inex1 = mpfr_set_si_2exp (x, s * i, -4, MPFR_RNDN);
68        MPFR_ASSERTN (inex1 == 0);
69        for (prec = 6; prec >= 3; prec -= 3)
70          {
71            mpfr_inits2 (prec, z1, z2, (mpfr_ptr) 0);
72            RND_LOOP_NO_RNDF (rnd)
73              for (k = 1; k <= 4; k++)
74                {
75                  /* The following one is assumed to be correct. */
76                  inex1 = mpfr_mul_2si (y, x, e, MPFR_RNDN);
77                  MPFR_ASSERTN (inex1 == 0);
78                  inex1 = mpfr_set_ui (z1, 1 << k, MPFR_RNDN);
79                  MPFR_ASSERTN (inex1 == 0);
80                  mpfr_clear_flags ();
81                  /* Do not use mpfr_div_ui to avoid the optimization
82                     by mpfr_div_2si. */
83                  inex1 = mpfr_div (z1, y, z1, (mpfr_rnd_t) rnd);
84                  flags1 = __gmpfr_flags;
85
86                  for (div = 0; div <= 2; div++)
87                    {
88                      mpfr_clear_flags ();
89                      inex2 =
90                        div == 0 ?
91                        mpfr_mul_2si (z2, x, e - k, (mpfr_rnd_t) rnd) :
92                        div == 1 ?
93                        mpfr_div_2si (z2, x, k - e, (mpfr_rnd_t) rnd) :
94                        mpfr_div_2ui (z2, x, k - e, (mpfr_rnd_t) rnd);
95                      flags2 = __gmpfr_flags;
96                      if (flags1 == flags2 && SAME_SIGN (inex1, inex2) &&
97                          mpfr_equal_p (z1, z2))
98                        continue;
99                      printf ("Error in underflow(");
100                      if (e == MPFR_EMIN_MIN)
101                        printf ("MPFR_EMIN_MIN");
102                      else if (e == emin)
103                        printf ("default emin");
104                      else
105                        printf ("%" MPFR_EXP_FSPEC "d", (mpfr_eexp_t) e);
106                      printf (") with mpfr_%s,\nx = %d/16, prec = %d, k = %d,"
107                              " %s\n", div == 0 ? "mul_2si" : div == 1 ?
108                              "div_2si" : "div_2ui", s * i, prec, k,
109                              mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
110                      printf ("Expected ");
111                      mpfr_out_str (stdout, 16, 0, z1, MPFR_RNDN);
112                      printf (", inex = %d, flags = %u\n",
113                              VSIGN (inex1), flags1);
114                      printf ("Got      ");
115                      mpfr_out_str (stdout, 16, 0, z2, MPFR_RNDN);
116                      printf (", inex = %d, flags = %u\n",
117                              VSIGN (inex2), flags2);
118                      exit (1);
119                    }  /* div */
120                }  /* k */
121            mpfr_clears (z1, z2, (mpfr_ptr) 0);
122          }  /* prec */
123      }  /* i */
124  mpfr_clears (x, y, (mpfr_ptr) 0);
125  set_emin (emin);
126}
127
128static void
129underflow0 (void)
130{
131  underflow (-256);
132  if (mpfr_get_emin () != MPFR_EMIN_MIN)
133    underflow (mpfr_get_emin ());
134  underflow (MPFR_EMIN_MIN);
135}
136
137static void
138large (mpfr_exp_t e)
139{
140  mpfr_t x, y, z;
141  mpfr_exp_t emax;
142  int inex;
143  unsigned int flags;
144
145  emax = mpfr_get_emax ();
146  set_emax (e);
147  mpfr_init2 (x, 8);
148  mpfr_init2 (y, 8);
149  mpfr_init2 (z, 4);
150
151  mpfr_set_inf (x, 1);
152  mpfr_nextbelow (x);
153
154  mpfr_mul_2si (y, x, -1, MPFR_RNDU);
155  mpfr_prec_round (y, 4, MPFR_RNDU);
156
157  mpfr_clear_flags ();
158  inex = mpfr_mul_2si (z, x, -1, MPFR_RNDU);
159  flags = __gmpfr_flags;
160
161  if (inex <= 0 || flags != MPFR_FLAGS_INEXACT || ! mpfr_equal_p (y, z))
162    {
163      printf ("Error in large(");
164      if (e == MPFR_EMAX_MAX)
165        printf ("MPFR_EMAX_MAX");
166      else if (e == emax)
167        printf ("default emax");
168      else
169        printf ("%" MPFR_EXP_FSPEC "d", (mpfr_eexp_t) e);
170      printf (") for mpfr_mul_2si\n");
171      printf ("Expected inex > 0, flags = %u,\n         y = ",
172              (unsigned int) MPFR_FLAGS_INEXACT);
173      mpfr_dump (y);
174      printf ("Got      inex = %d, flags = %u,\n         y = ",
175              inex, flags);
176      mpfr_dump (z);
177      exit (1);
178    }
179
180  mpfr_clear_flags ();
181  inex = mpfr_div_2si (z, x, 1, MPFR_RNDU);
182  flags = __gmpfr_flags;
183
184  if (inex <= 0 || flags != MPFR_FLAGS_INEXACT || ! mpfr_equal_p (y, z))
185    {
186      printf ("Error in large(");
187      if (e == MPFR_EMAX_MAX)
188        printf ("MPFR_EMAX_MAX");
189      else if (e == emax)
190        printf ("default emax");
191      else
192        printf ("%" MPFR_EXP_FSPEC "d", (mpfr_eexp_t) e);
193      printf (") for mpfr_div_2si\n");
194      printf ("Expected inex > 0, flags = %u,\n         y = ",
195              (unsigned int) MPFR_FLAGS_INEXACT);
196      mpfr_dump (y);
197      printf ("Got      inex = %d, flags = %u,\n         y = ",
198              inex, flags);
199      mpfr_dump (z);
200      exit (1);
201    }
202
203  mpfr_clear_flags ();
204  inex = mpfr_div_2ui (z, x, 1, MPFR_RNDU);
205  flags = __gmpfr_flags;
206
207  if (inex <= 0 || flags != MPFR_FLAGS_INEXACT || ! mpfr_equal_p (y, z))
208    {
209      printf ("Error in large(");
210      if (e == MPFR_EMAX_MAX)
211        printf ("MPFR_EMAX_MAX");
212      else if (e == emax)
213        printf ("default emax");
214      else
215        printf ("%" MPFR_EXP_FSPEC "d", (mpfr_eexp_t) e);
216      printf (") for mpfr_div_2ui\n");
217      printf ("Expected inex > 0, flags = %u,\n         y = ",
218              (unsigned int) MPFR_FLAGS_INEXACT);
219      mpfr_dump (y);
220      printf ("Got      inex = %d, flags = %u,\n         y = ",
221              inex, flags);
222      mpfr_dump (z);
223      exit (1);
224    }
225
226  mpfr_clears (x, y, z, (mpfr_ptr) 0);
227  set_emax (emax);
228}
229
230static void
231large0 (void)
232{
233  mpfr_exp_t emin;
234
235  emin = mpfr_get_emin ();
236
237  while (1)
238    {
239      large (256);
240      if (mpfr_get_emax () != MPFR_EMAX_MAX)
241        large (mpfr_get_emax ());
242      large (MPFR_EMAX_MAX);
243      if (mpfr_get_emin () == MPFR_EMIN_MIN)
244        break;
245      /* Redo the test with __gmpfr_emin set to MPFR_EMIN_MIN, which can
246         be useful to trigger integer overflows as in div_2ui.c r12272. */
247      set_emin (MPFR_EMIN_MIN);
248    }
249
250  set_emin (emin);
251}
252
253/* Cases where the function overflows on n = 0 when rounding is like
254   away from zero. */
255static void
256overflow0 (mpfr_exp_t emax)
257{
258  mpfr_exp_t old_emax;
259  mpfr_t x, y1, y2;
260  int neg, r, op;
261  static const char *sop[4] = { "mul_2ui", "mul_2si", "div_2ui", "div_2si" };
262
263  old_emax = mpfr_get_emax ();
264  set_emax (emax);
265
266  mpfr_init2 (x, 8);
267  mpfr_inits2 (6, y1, y2, (mpfr_ptr) 0);
268
269  mpfr_set_inf (x, 1);
270  mpfr_nextbelow (x);
271
272  for (neg = 0; neg <= 1; neg++)
273    {
274      RND_LOOP_NO_RNDF (r)
275        {
276          int inex1, inex2;
277          mpfr_flags_t flags1, flags2;
278
279          /* Even if there isn't an overflow (rounding ~ toward zero),
280             the result is the same as the one of an overflow. */
281          inex1 = mpfr_overflow (y1, (mpfr_rnd_t) r, neg ? -1 : 1);
282          flags1 = MPFR_FLAGS_INEXACT;
283          if (mpfr_inf_p (y1))
284            flags1 |= MPFR_FLAGS_OVERFLOW;
285          for (op = 0; op < 4; op++)
286            {
287              mpfr_clear_flags ();
288              inex2 =
289                op == 0 ? mpfr_mul_2ui (y2, x, 0, (mpfr_rnd_t) r) :
290                op == 1 ? mpfr_mul_2si (y2, x, 0, (mpfr_rnd_t) r) :
291                op == 2 ? mpfr_div_2ui (y2, x, 0, (mpfr_rnd_t) r) :
292                op == 3 ? mpfr_div_2si (y2, x, 0, (mpfr_rnd_t) r) :
293                (MPFR_ASSERTN (0), 0);
294              flags2 = __gmpfr_flags;
295              if (!(mpfr_equal_p (y1, y2) &&
296                    SAME_SIGN (inex1, inex2) &&
297                    flags1 == flags2))
298                {
299                  printf ("Error in overflow0 for %s, mpfr_%s, emax = %"
300                          MPFR_EXP_FSPEC "d,\nx = ",
301                          mpfr_print_rnd_mode ((mpfr_rnd_t) r), sop[op],
302                          (mpfr_eexp_t) emax);
303                  mpfr_dump (x);
304                  printf ("Expected ");
305                  mpfr_dump (y1);
306                  printf ("  with inex = %d, flags =", inex1);
307                  flags_out (flags1);
308                  printf ("Got      ");
309                  mpfr_dump (y2);
310                  printf ("  with inex = %d, flags =", inex2);
311                  flags_out (flags2);
312                  exit (1);
313                }
314            }
315        }
316      mpfr_neg (x, x, MPFR_RNDN);
317    }
318
319  mpfr_clears (x, y1, y2, (mpfr_ptr) 0);
320  set_emax (old_emax);
321}
322
323static void
324coverage_div_2ui (void)
325{
326  mpfr_t x, y;
327
328  mpfr_init2 (x, 2);
329  mpfr_init2 (y, 2);
330  mpfr_set_ui_2exp (x, 1, mpfr_get_emax () - 1, MPFR_RNDN);
331  mpfr_div_2ui (y, x, (unsigned long) LONG_MAX + 1, MPFR_RNDN);
332  MPFR_ASSERTN(mpfr_zero_p (y));
333  MPFR_ASSERTN(mpfr_signbit (y) == 0);
334  mpfr_clear (x);
335  mpfr_clear (y);
336}
337
338int
339main (int argc, char *argv[])
340{
341  mpfr_t w,z;
342  unsigned long k;
343  int i;
344
345  tests_start_mpfr ();
346
347  coverage_div_2ui ();
348  mpfr_inits2 (53, w, z, (mpfr_ptr) 0);
349
350  for (i = 0; i < 3; i++)
351    {
352      mpfr_set_inf (w, 1);
353      test_mul (i, 0, w, w, 10, MPFR_RNDZ);
354      if (!MPFR_IS_INF(w))
355        {
356          printf ("Result is not Inf (i = %d)\n", i);
357          exit (1);
358        }
359
360      mpfr_set_nan (w);
361      test_mul (i, 0, w, w, 10, MPFR_RNDZ);
362      if (!MPFR_IS_NAN(w))
363        {
364          printf ("Result is not NaN (i = %d)\n", i);
365          exit (1);
366        }
367
368      for (k = 0 ; k < numberof(val) ; k+=3)
369        {
370          mpfr_set_str (w, val[k], 16, MPFR_RNDN);
371          test_mul (i, 0, z, w, 10, MPFR_RNDZ);
372          if (mpfr_cmp_str (z, val[k+1], 16, MPFR_RNDN))
373            {
374              printf ("ERROR for x * 2^n (i = %d) for %s\n", i, val[k]);
375              printf ("Expected: %s\n"
376                      "Got     : ", val[k+1]);
377              mpfr_out_str (stdout, 16, 0, z, MPFR_RNDN);
378              putchar ('\n');
379              exit (1);
380            }
381          test_mul (i, 1, z, w, 10, MPFR_RNDZ);
382          if (mpfr_cmp_str (z, val[k+2], 16, MPFR_RNDN))
383            {
384              printf ("ERROR for x / 2^n (i = %d) for %s\n", i, val[k]);
385              printf ("Expected: %s\n"
386                      "Got     : ", val[k+2]);
387              mpfr_out_str (stdout, 16, 0, z, MPFR_RNDN);
388              putchar ('\n');
389              exit (1);
390            }
391        }
392
393      mpfr_set_inf (w, 1);
394      mpfr_nextbelow (w);
395      test_mul (i, 0, w, w, 1, MPFR_RNDN);
396      if (!mpfr_inf_p (w))
397        {
398          printf ("Overflow error (i = %d)!\n", i);
399          exit (1);
400        }
401      mpfr_set_ui (w, 0, MPFR_RNDN);
402      mpfr_nextabove (w);
403      test_mul (i, 1, w, w, 1, MPFR_RNDN);
404      if (mpfr_cmp_ui (w, 0))
405        {
406          printf ("Underflow error (i = %d)!\n", i);
407          exit (1);
408        }
409    }
410
411  if (MPFR_EXP_MAX >= LONG_MAX/2 && MPFR_EXP_MIN <= LONG_MAX/2-LONG_MAX-1)
412    {
413      unsigned long lmp1 = (unsigned long) LONG_MAX + 1;
414
415      mpfr_set_ui (w, 1, MPFR_RNDN);
416      mpfr_mul_2ui (w, w, LONG_MAX/2, MPFR_RNDZ);
417      mpfr_div_2ui (w, w, lmp1, MPFR_RNDZ);
418      mpfr_mul_2ui (w, w, lmp1 - LONG_MAX/2, MPFR_RNDZ);
419      if (!mpfr_cmp_ui (w, 1))
420        {
421          printf ("Underflow LONG_MAX error!\n");
422          exit (1);
423        }
424    }
425
426  mpfr_clears (w, z, (mpfr_ptr) 0);
427
428  underflow0 ();
429  large0 ();
430
431  if (mpfr_get_emax () != MPFR_EMAX_MAX)
432    overflow0 (mpfr_get_emax ());
433  overflow0 (MPFR_EMAX_MAX);
434  overflow0 (-1);
435
436  tests_end_mpfr ();
437  return 0;
438}
439