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/* Test mpf_get_d_2exp.
Copyright 2002, 2003, 2017, 2020 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-impl.h"
#include "tests.h"
static void
check_data (void)
{
mpf_t f;
double got, want;
long got_exp;
long exp;
struct {
int base;
int shift;
} data[] = {
{-1, 1}, {-3, 2}, {-5, 3}, {-7, 3}, { 1, 1}, { 3, 2}, { 5, 3}, { 7, 3}
};
mpf_init2 (f, 3);
got = mpf_get_d_2exp (&got_exp, f);
if (got != 0 || got_exp != 0)
{
printf ("mpf_get_d_2exp wrong on zero\n");
mpf_trace (" f ", f);
d_trace (" got ", got);
printf (" got exp %ld\n", got_exp);
abort();
}
for (exp = -513; exp <= 513; exp++)
{
size_t i;
for (i = 0; i < numberof (data); i++)
{
want = (double) data[i].base / (1 << data[i].shift);
mpf_set_d (f, want);
if (exp >= 0)
mpf_mul_2exp (f, f, exp);
else
mpf_div_2exp (f, f, -exp);
got = mpf_get_d_2exp (&got_exp, f);
if (got != want || got_exp != exp)
{
printf ("mpf_get_d_2exp wrong on 2**%ld\n", exp);
mpf_trace (" f ", f);
d_trace (" want ", want);
d_trace (" got ", got);
printf (" want exp %ld\n", 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_data ();
check_round ();
tests_end ();
exit (0);
}
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