/* Test mpz_get_d_2exp.

Copyright 2002, 2003, 2012 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_zero (void)

{

  mpz_t   z;

  double  got, want;

  long    got_exp, want_exp;

  mpz_init_set_ui (z, 0);

  want = 0.0;

  want_exp = 0;

  got = mpz_get_d_2exp (&got_exp, z);

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

    {

      printf    ("mpz_get_d_2exp wrong on zero\n");

      mpz_trace ("   z    ", z);

      d_trace   ("   want ", want);

      d_trace   ("   got  ", got);

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

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

      abort();

    }

  mpz_clear (z);

}

static void

check_onebit (void)

{

  static const unsigned long data[] = {

    1, 32, 52, 53, 54, 63, 64, 65, 128, 256, 511, 512, 513

  };

  mpz_t   z;

  double  got, want;

  long    got_exp, want_exp;

  int     i;

  mpz_init (z);

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

    {

      mpz_set_ui (z, 1L);

      mpz_mul_2exp (z, z, data[i]);

      want = 0.5;

      want_exp = data[i] + 1;

      got = mpz_get_d_2exp (&got_exp, z);

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

        {

          printf    ("mpz_get_d_2exp wrong on 2**%ld\n", data[i]);

          mpz_trace ("   z    ", z);

          d_trace   ("   want ", want);

          d_trace   ("   got  ", got);

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

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

          abort();

        }

      mpz_set_si (z, -1L);

      mpz_mul_2exp (z, z, data[i]);

      want = -0.5;

      want_exp = data[i] + 1;

      got = mpz_get_d_2exp (&got_exp, z);

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

        {

          printf    ("mpz_get_d_2exp wrong on -2**%ld\n", data[i]);

          mpz_trace ("   z    ", z);

          d_trace   ("   want ", want);

          d_trace   ("   got  ", got);

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

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

          abort();

        }

    }

  mpz_clear (z);

}

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

  mpz_t   z;

  double  got;

  long    got_exp;

  int     i, rnd_mode, old_rnd_mode;

  mpz_init (z);

  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++)

        {

          mpz_set_ui (z, 1L);

          mpz_mul_2exp (z, z, data[i]);

          mpz_sub_ui (z, z, 1L);

          got = mpz_get_d_2exp (&got_exp, z);

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

            {

              printf    ("mpz_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]);

              mpz_trace ("   z    ", z);

              d_trace   ("   got  ", got);

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

              abort();

            }

          mpz_neg (z, z);

          got = mpz_get_d_2exp (&got_exp, z);

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

            {

              printf    ("mpz_get_d_2exp wrong on -2**%lu-1\n", data[i]);

              printf    ("result out of range, expect -1.0 < got <= -0.5\n");

              printf    ("   rnd_mode = %d\n", rnd_mode);

              printf    ("   data[i]  = %lu\n", data[i]);

              mpz_trace ("   z    ", z);

              d_trace   ("   got  ", got);

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

              abort();

            }

        }

    }

  mpz_clear (z);

  tests_hardware_setround (old_rnd_mode);

}

static void

check_rand (void)

{

  gmp_randstate_ptr rands = RANDS;

  int     i;

  mpz_t   z;

  double  got;

  long    got_exp;

  unsigned long  bits;

  mpz_init (z);

  for (i = 0; i < 200; i++)

    {

      bits = gmp_urandomm_ui (rands, 512L);

      mpz_urandomb (z, rands, bits);

      got = mpz_get_d_2exp (&got_exp, z);

      if (mpz_sgn (z) == 0)

        continue;

      bits = mpz_sizeinbase (z, 2);

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

        {

          printf    ("mpz_get_d_2exp out of range, expect 0.5 <= got < 1.0\n");

          mpz_trace ("   z    ", z);

          d_trace   ("   got  ", got);

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

          abort();

        }

      /* FIXME: If mpz_get_d_2exp rounds upwards we might have got_exp ==

         bits+1, so leave this test disabled until we decide if that's what

         should happen, or not.  */

#if 0

      if (got_exp != bits)

        {

          printf    ("mpz_get_d_2exp wrong exponent\n", i);

          mpz_trace ("   z    ", z);

          d_trace   ("   bits ", bits);

          d_trace   ("   got  ", got);

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

          abort();

        }

#endif

    }

  mpz_clear (z);

}

int

main (void)

{

  tests_start ();

  mp_trace_base = -16;

  check_zero ();

  check_onebit ();

  check_round ();

  check_rand ();

  tests_end ();

  exit (0);

}