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/* Test of splitting a 'long double' into fraction and mantissa.
Copyright (C) 2007-2025 Free Software Foundation, Inc.
This program 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.
This program 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 this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
#include <config.h>
#include "printf-frexpl.h"
#include <float.h>
#include "fpucw.h"
#include "macros.h"
/* On PowerPC machines, LDBL_MIN_EXP is -1021, but the smallest reliable
exponent for 'long double' is -968. For exponents below that, the precision
may be truncated to the precision used for 'double'. */
#if defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__
# define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53)
# define MIN_SUBNORMAL_EXP MIN_NORMAL_EXP
#else
# define MIN_NORMAL_EXP LDBL_MIN_EXP
# define MIN_SUBNORMAL_EXP (LDBL_MIN_EXP - 100)
#endif
static long double
my_ldexp (long double x, int d)
{
for (; d > 0; d--)
x *= 2.0L;
for (; d < 0; d++)
x *= 0.5L;
return x;
}
int
main ()
{
int i;
long double x;
DECL_LONG_DOUBLE_ROUNDING
BEGIN_LONG_DOUBLE_ROUNDING ();
for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.0L);
}
for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.0L);
}
for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == LDBL_MIN_EXP - 1);
ASSERT (mantissa == my_ldexp (1.0L, i - LDBL_MIN_EXP));
}
for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.01L);
}
for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.01L);
}
for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == LDBL_MIN_EXP - 1);
ASSERT (mantissa >= my_ldexp (1.0L, i - LDBL_MIN_EXP));
ASSERT (mantissa <= my_ldexp (2.0L, i - LDBL_MIN_EXP));
ASSERT (mantissa == my_ldexp (x, - exp));
}
for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.73205L);
}
for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == i - 1);
ASSERT (mantissa == 1.73205L);
}
for (; i >= MIN_SUBNORMAL_EXP && x > 0.0L; i--, x *= 0.5L)
{
int exp = -9999;
long double mantissa = printf_frexpl (x, &exp);
ASSERT (exp == LDBL_MIN_EXP - 1);
ASSERT (mantissa >= my_ldexp (1.0L, i - LDBL_MIN_EXP));
ASSERT (mantissa <= my_ldexp (2.0L, i - LDBL_MIN_EXP));
ASSERT (mantissa == my_ldexp (x, - exp));
}
return test_exit_status;
}
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