1  /* Test file for mpfr_d_sub
       2  
       3  Copyright 2007-2023 Free Software Foundation, Inc.
       4  Contributed by the AriC and Caramba projects, INRIA.
       5  
       6  This file is part of the GNU MPFR Library.
       7  
       8  The GNU MPFR Library is free software; you can redistribute it and/or modify
       9  it under the terms of the GNU Lesser General Public License as published by
      10  the Free Software Foundation; either version 3 of the License, or (at your
      11  option) any later version.
      12  
      13  The GNU MPFR Library is distributed in the hope that it will be useful, but
      14  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      15  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      16  License for more details.
      17  
      18  You should have received a copy of the GNU Lesser General Public License
      19  along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
      20  https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
      21  51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
      22  
      23  #include <float.h>
      24  
      25  #include "mpfr-test.h"
      26  
      27  static void
      28  check_nans (void)
      29  {
      30    mpfr_t  x, y;
      31    int inexact;
      32  
      33    mpfr_init2 (x, 123);
      34    mpfr_init2 (y, 123);
      35  
      36    /* 1.0 - nan is nan */
      37    mpfr_set_nan (x);
      38    mpfr_clear_flags ();
      39    inexact = mpfr_d_sub (y, 1.0, x, MPFR_RNDN);
      40    MPFR_ASSERTN (inexact == 0);
      41    MPFR_ASSERTN (__gmpfr_flags == MPFR_FLAGS_NAN);
      42    MPFR_ASSERTN (mpfr_nan_p (y));
      43  
      44    /* 1.0 - +inf == -inf */
      45    mpfr_set_inf (x, 1);
      46    mpfr_clear_flags ();
      47    inexact = mpfr_d_sub (y, 1.0, x, MPFR_RNDN);
      48    MPFR_ASSERTN (inexact == 0);
      49    MPFR_ASSERTN (__gmpfr_flags == 0);
      50    MPFR_ASSERTN (mpfr_inf_p (y));
      51    MPFR_ASSERTN (MPFR_IS_NEG (y));
      52  
      53    /* 1.0 - -inf == +inf */
      54    mpfr_set_inf (x, -1);
      55    mpfr_clear_flags ();
      56    inexact = mpfr_d_sub (y, 1.0, x, MPFR_RNDN);
      57    MPFR_ASSERTN (inexact == 0);
      58    MPFR_ASSERTN (__gmpfr_flags == 0);
      59    MPFR_ASSERTN (mpfr_inf_p (y));
      60    MPFR_ASSERTN (MPFR_IS_POS (y));
      61  
      62    mpfr_clear (x);
      63    mpfr_clear (y);
      64  }
      65  
      66  #define TEST_FUNCTION mpfr_d_sub
      67  #define DOUBLE_ARG1
      68  #define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
      69  #include "tgeneric.c"
      70  
      71  int
      72  main (void)
      73  {
      74    mpfr_t x, y, z;
      75    double d;
      76    int inexact;
      77  
      78    tests_start_mpfr ();
      79  
      80    /* check with enough precision */
      81    mpfr_init2 (x, IEEE_DBL_MANT_DIG);
      82    mpfr_init2 (y, IEEE_DBL_MANT_DIG);
      83    mpfr_init2 (z, IEEE_DBL_MANT_DIG);
      84  
      85    mpfr_set_str (y, "4096", 10, MPFR_RNDN);
      86    d = 0.125;
      87    mpfr_clear_flags ();
      88    inexact = mpfr_d_sub (x, d, y, MPFR_RNDN);
      89    if (inexact != 0)
      90      {
      91        printf ("Inexact flag error in mpfr_d_sub\n");
      92        exit (1);
      93      }
      94    mpfr_set_str (z, "-4095.875", 10, MPFR_RNDN);
      95    if (mpfr_cmp (z, x))
      96      {
      97        printf ("Error in mpfr_d_sub (");
      98        mpfr_out_str (stdout, 10, 7, y, MPFR_RNDN);
      99        printf (" + %.20g)\nexpected ", d);
     100        mpfr_out_str (stdout, 10, 0, z, MPFR_RNDN);
     101        printf ("\ngot     ");
     102        mpfr_out_str (stdout, 10, 0, x, MPFR_RNDN);
     103        printf ("\n");
     104        exit (1);
     105      }
     106    mpfr_clears (x, y, z, (mpfr_ptr) 0);
     107  
     108    check_nans ();
     109  
     110    test_generic (MPFR_PREC_MIN, 1000, 100);
     111  
     112    tests_end_mpfr ();
     113    return 0;
     114  }