mpfr-2.4.1/tests/tget_d_2exp.c

/* Test mpfr_get_d_2exp.

Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>
#include <float.h>

#include "mpfr-test.h"


/* Check that hardware rounding doesn't make mpfr_get_d_2exp return a value
   outside its defined range. */
static void
check_round (void)
{
  static const unsigned long data[] = { 1, 32, 53, 54, 64, 128, 256, 512 };
  mpfr_t  f;
  double  got;
  long    got_exp;
  int     i, rnd_mode, neg;

  mpfr_init2 (f, 1024L);

  for (rnd_mode = 0; rnd_mode < GMP_RND_MAX ; rnd_mode++)
    {
      for (i = 0; i < (int) numberof (data); i++)
        {
          mpfr_set_ui (f, 1L, GMP_RNDZ);
          mpfr_mul_2exp (f, f, data[i], GMP_RNDZ);
          mpfr_sub_ui (f, f, 1L, GMP_RNDZ);

          for (neg = 0; neg <= 1; neg++)
            {
              got = mpfr_get_d_2exp (&got_exp, f, (mp_rnd_t) rnd_mode);

              if (neg == 0
                  ? (got < 0.5 || got >= 1.0)
                  : (got <= -1.0 || got > -0.5))
                {
                  printf  ("mpfr_get_d_2exp wrong on 2**%lu-1\n", data[i]);
                  printf  ("result out of range, expect 0.5 <= got < 1.0\n");
                  printf  ("   rnd_mode = %d\n", rnd_mode);
                  printf  ("   data[i]  = %lu\n", data[i]);
                  printf  ("   f    ");
                  mpfr_out_str (stdout, 2, 0, f, GMP_RNDN);
                  printf  ("\n");
                  d_trace ("   got  ", got);
                  printf  ("   got exp  %ld\n", got_exp);
                  exit(1);
                }

              mpfr_neg (f, f, GMP_RNDZ);
            }
        }
    }

  mpfr_clear (f);
}


static void
check_inf_nan (void)
{
  /* only if nans and infs are available */
#if _GMP_IEEE_FLOATS
  mpfr_t  x;
  double  d;
  long    exp;

  mpfr_init2 (x, 123);

  mpfr_set_inf (x, 1);
  d = mpfr_get_d_2exp (&exp, x, GMP_RNDZ);
  ASSERT_ALWAYS (d > 0);
  ASSERT_ALWAYS (DOUBLE_ISINF (d));

  mpfr_set_inf (x, -1);
  d = mpfr_get_d_2exp (&exp, x, GMP_RNDZ);
  ASSERT_ALWAYS (d < 0);
  ASSERT_ALWAYS (DOUBLE_ISINF (d));

  mpfr_set_nan (x);
  d = mpfr_get_d_2exp (&exp, x, GMP_RNDZ);
  ASSERT_ALWAYS (DOUBLE_ISNAN (d));

  mpfr_clear (x);
#endif
}


int
main (void)
{
  tests_start_mpfr ();
  mpfr_test_init ();

  check_round ();
  check_inf_nan ();

  tests_end_mpfr ();
  return 0;
}