/* Test mpf_get_d_2exp.

Copyright 2002, 2003 Free Software Foundation, Inc.

This file is part of the GNU MP Library test suite.

The GNU MP Library test suite is free software; you can redistribute it

and/or modify it under the terms of the GNU 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 MP Library test suite 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 General

Public License for more details.

You should have received a copy of the GNU General Public License along with

the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */

#include <stdio.h>

#include <stdlib.h>

#include "gmp.h"

#include "gmp-impl.h"

#include "tests.h"

static void

check_onebit (void)

{

  static const long data[] = {

    -513, -512, -511, -65, -64, -63, -32, -1,

    0, 1, 32, 53, 54, 64, 128, 256, 511, 512, 513

  };

  mpf_t   f;

  double  got, want;

  long    got_exp, want_exp;

  int     i;

  mpf_init2 (f, 1024L);

  for (i = 0; i < numberof (data); i++)

    {

      mpf_set_ui (f, 1L);

      if (data[i] >= 0)

        mpf_mul_2exp (f, f, data[i]);

      else

        mpf_div_2exp (f, f, -data[i]);

      want = 0.5;

      want_exp = data[i] + 1;

      got = mpf_get_d_2exp (&got_exp, f);

      if (got != want || got_exp != want_exp)

        {

          printf    ("mpf_get_d_2exp wrong on 2**%ld\n", data[i]);

          mpf_trace ("   f    ", f);

          d_trace   ("   want ", want);

          d_trace   ("   got  ", got);

          printf    ("   want exp %ld\n", want_exp);

          printf    ("   got exp  %ld\n", got_exp);

          abort();

        }

    }

  mpf_clear (f);

}

/* Check that hardware rounding doesn't make mpf_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 };

  mpf_t   f;

  double  got;

  long    got_exp;

  int     i, rnd_mode, old_rnd_mode;

  mpf_init2 (f, 1024L);

  old_rnd_mode = tests_hardware_getround ();

  for (rnd_mode = 0; rnd_mode < 4; rnd_mode++)

    {

      tests_hardware_setround (rnd_mode);

      for (i = 0; i < numberof (data); i++)

        {

          mpf_set_ui (f, 1L);

          mpf_mul_2exp (f, f, data[i]);

          mpf_sub_ui (f, f, 1L);

          got = mpf_get_d_2exp (&got_exp, f);

          if (got < 0.5 || got >= 1.0)

            {

              printf    ("mpf_get_d_2exp bad 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]);

              mpf_trace ("   f    ", f);

              d_trace   ("   got  ", got);

              printf    ("   got exp  %ld\n", got_exp);

              abort();

            }

        }

    }

  mpf_clear (f);

  tests_hardware_setround (old_rnd_mode);

}

int

main (void)

{

  tests_start ();

  mp_trace_base = 16;

  check_onebit ();

  check_round ();

  tests_end ();

  exit (0);

}