path: root/tests/tset_ld.c

/* Test file for mpfr_set_ld and mpfr_get_ld.

Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
Contributed by the AriC and Caramel 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 3 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.LESSER.  If not, see
http://www.gnu.org/licenses/ or 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 <limits.h>
#ifdef WITH_FPU_CONTROL
#include <fpu_control.h>
#endif

#include "mpfr-test.h"

static void
check_gcc33_bug (void)
{
  volatile long double x;
  x = (long double) 9007199254740992.0 + 1.0;
  if (x != 0.0)
    return;  /* OK */
  printf
    ("Detected optimization bug of gcc 3.3 on Alpha concerning long double\n"
     "comparisons; set_ld tests might fail (set_ld won't work correctly).\n"
     "See http://gcc.gnu.org/ml/gcc-bugs/2003-10/msg00853.html for more\n"
     "information.\n");
}

static int
Isnan_ld (long double d)
{
  double e = (double) d;
  if (DOUBLE_ISNAN (e))
    return 1;
  LONGDOUBLE_NAN_ACTION (d, goto yes);
  return 0;
 yes:
  return 1;
}

/* checks that a long double converted to a mpfr (with precision >=113),
   then converted back to a long double gives the initial value,
   or in other words mpfr_get_ld(mpfr_set_ld(d)) = d.
*/
static void
check_set_get (long double d, mpfr_t x)
{
  int r;
  long double e;
  int inex;

  for (r = 0; r < MPFR_RND_MAX; r++)
    {
      inex = mpfr_set_ld (x, d, (mpfr_rnd_t) r);
      if (inex != 0)
        {
          mpfr_exp_t emin, emax;
          emin = mpfr_get_emin ();
          emax = mpfr_get_emax ();
          printf ("Error: mpfr_set_ld should be exact\n");
          printf ("d=%1.30Le inex=%d\n", d, inex);
          if (emin >= LONG_MIN)
            printf ("emin=%ld\n", (long) emin);
          if (emax <= LONG_MAX)
            printf ("emax=%ld\n", (long) emax);
          mpfr_dump (x);
          exit (1);
        }
      e = mpfr_get_ld (x, (mpfr_rnd_t) r);
      if ((Isnan_ld(d) && ! Isnan_ld(e)) ||
          (Isnan_ld(e) && ! Isnan_ld(d)) ||
          (e != d && !(Isnan_ld(e) && Isnan_ld(d))))
        {
          printf ("Error: mpfr_get_ld o mpfr_set_ld <> Id\n");
          printf ("  r=%d\n", r);
          printf ("  d=%1.30Le get_ld(set_ld(d))=%1.30Le\n", d, e);
          ld_trace ("  d", d);
          printf ("  x="); mpfr_out_str (NULL, 16, 0, x, MPFR_RNDN);
          printf ("\n");
          ld_trace ("  e", e);
#ifdef MPFR_NANISNAN
          if (Isnan_ld(d) || Isnan_ld(e))
            printf ("The reason is that NAN == NAN. Please look at the "
                    "configure output\nand Section \"In case of problem\" "
                    "of the INSTALL file.\n");
#endif
          exit (1);
        }
    }
}

static void
test_small (void)
{
  mpfr_t x, y, z;
  long double d;

  mpfr_init2 (x, 64);
  mpfr_init2 (y, 64);
  mpfr_init2 (z, 64);

  /* x = 11906603631607553907/2^(16381+64) */
  mpfr_set_str (x, "0.1010010100111100110000001110101101000111010110000001111101110011E-16381", 2, MPFR_RNDN);
  d = mpfr_get_ld (x, MPFR_RNDN);  /* infinite loop? */
  mpfr_set_ld (y, d, MPFR_RNDN);
  mpfr_sub (z, x, y, MPFR_RNDN);
  mpfr_abs (z, z, MPFR_RNDN);
  mpfr_clear_erangeflag ();
  /* If long double = double, d should be equal to 0;
     in this case, everything is OK. */
  if (d != 0 && (mpfr_cmp_str (z, "1E-16434", 2, MPFR_RNDN) > 0 ||
                 mpfr_erangeflag_p ()))
    {
      printf ("Error with x = ");
      mpfr_out_str (NULL, 10, 21, x, MPFR_RNDN);
      printf (" = ");
      mpfr_out_str (NULL, 16, 0, x, MPFR_RNDN);
      printf ("\n        -> d = %.21Lg", d);
      printf ("\n        -> y = ");
      mpfr_out_str (NULL, 10, 21, y, MPFR_RNDN);
      printf (" = ");
      mpfr_out_str (NULL, 16, 0, y, MPFR_RNDN);
      printf ("\n        -> |x-y| = ");
      mpfr_out_str (NULL, 16, 0, z, MPFR_RNDN);
      printf ("\n");
      exit (1);
    }

  mpfr_clear (x);
  mpfr_clear (y);
  mpfr_clear (z);
}

static void
test_fixed_bugs (void)
{
  mpfr_t x;
  long double l, m;

  /* bug found by Steve Kargl (2009-03-14) */
  mpfr_init2 (x, 64);
  mpfr_set_ui_2exp (x, 1, -16447, MPFR_RNDN);
  mpfr_get_ld (x, MPFR_RNDN);  /* an assertion failed in init2.c:50 */

  /* bug reported by Jakub Jelinek (2010-10-17)
     https://gforge.inria.fr/tracker/?func=detail&aid=11300 */
  mpfr_set_prec (x, MPFR_LDBL_MANT_DIG);
  /* l = 0x1.23456789abcdef0123456789abcdp-914L; */
  l = 8.215640181713713164092636634579e-276;
  mpfr_set_ld (x, l, MPFR_RNDN);
  m = mpfr_get_ld (x, MPFR_RNDN);
  if (m != l)
    {
      printf ("Error in get_ld o set_ld for l=%Le\n", l);
      printf ("Got m=%Le instead of l\n", m);
      exit (1);
    }

  /* another similar test which failed with extended double precision and the
     generic code for mpfr_set_ld */
  /* l = 0x1.23456789abcdef0123456789abcdp-968L; */
  l = 4.560596445887084662336528403703e-292;
  mpfr_set_ld (x, l, MPFR_RNDN);
  m = mpfr_get_ld (x, MPFR_RNDN);
  if (m != l)
    {
      printf ("Error in get_ld o set_ld for l=%Le\n", l);
      printf ("Got m=%Le instead of l\n", m);
      exit (1);
    }

  mpfr_clear (x);
}

int
main (int argc, char *argv[])
{
  long double d, e;
  mpfr_t x;
  int i;
  mpfr_exp_t emax;
#ifdef WITH_FPU_CONTROL
  fpu_control_t cw;

  if (argc > 1)
    {
      cw = strtol(argv[1], NULL, 0);
      printf ("FPU control word: 0x%x\n", (unsigned int) cw);
      _FPU_SETCW (cw);
    }
#endif

  check_gcc33_bug ();
  test_fixed_bugs ();

  tests_start_mpfr ();
  mpfr_test_init ();

  mpfr_init2 (x, MPFR_LDBL_MANT_DIG);

#if !defined(MPFR_ERRDIVZERO)
  /* check NaN */
  mpfr_set_nan (x);
  d = mpfr_get_ld (x, MPFR_RNDN);
  check_set_get (d, x);
#endif

  /* check +0.0 and -0.0 */
  d = 0.0;
  check_set_get (d, x);
  d = DBL_NEG_ZERO;
  check_set_get (d, x);

  /* check that the sign of -0.0 is set */
  mpfr_set_ld (x, DBL_NEG_ZERO, MPFR_RNDN);
  if (MPFR_SIGN(x) > 0)
    {
      printf ("Error: sign of -0.0 is not set correctly\n");
#if _GMP_IEEE_FLOATS
      exit (1);
      /* Non IEEE doesn't support negative zero yet */
#endif
    }

#if !defined(MPFR_ERRDIVZERO)
  /* check +Inf */
  mpfr_set_inf (x, 1);
  d = mpfr_get_ld (x, MPFR_RNDN);
  check_set_get (d, x);

  /* check -Inf */
  mpfr_set_inf (x, -1);
  d = mpfr_get_ld (x, MPFR_RNDN);
  check_set_get (d, x);
#endif

  /* check the largest power of two */
  d = 1.0; while (d < LDBL_MAX / 2.0) d += d;
  check_set_get (d, x);
  check_set_get (-d, x);

  /* check largest long double */
  d = LDBL_MAX;
  check_set_get (d, x);
  check_set_get (-d, x);

  /* check the smallest power of two */
  d = 1.0;
  while ((e = d / 2.0) != (long double) 0.0 && e != d)
    d = e;
  check_set_get (d, x);
  check_set_get (-d, x);

  /* check largest 2^(2^k) that is representable as a long double */
  d = (LDBL_MAX / 2) + (LDBL_MAX / 4 * LDBL_EPSILON);
  check_set_get (d, x);

  /* check that 2^i, 2^i+1 and 2^i-1 are correctly converted */
  d = 1.0;
  for (i = 1; i < MPFR_LDBL_MANT_DIG; i++)
    {
      d = 2.0 * d; /* d = 2^i */
      check_set_get (d, x);
      check_set_get (d + 1.0, x);
      check_set_get (d - 1.0, x);
    }

  for (i = 0; i < 10000; i++)
    {
      mpfr_urandomb (x, RANDS);
      d = mpfr_get_ld (x, MPFR_RNDN);
      check_set_get (d, x);
    }

  /* check with reduced emax to exercise overflow */
  emax = mpfr_get_emax ();
  mpfr_set_prec (x, 2);
  set_emax (1);
  mpfr_set_ld (x, (long double) 2.0, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_inf_p (x) && mpfr_sgn (x) > 0);
  for (d = (long double) 2.0, i = 0; i < 13; i++, d *= d);
  /* now d = 2^8192 */
  mpfr_set_ld (x, d, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_inf_p (x) && mpfr_sgn (x) > 0);
  set_emax (emax);

  mpfr_clear (x);

  test_small ();

  tests_end_mpfr ();

  return 0;
}