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/* Break dfp number into normalized fraction and integral power of two
Copyright (C) 2006 IBM Corporation.
Copyright (C) 2007-2015 Free Software Foundation, Inc.
This file is part of the Decimal Floating Point C Library.
Author(s): Joseph Kerian <jkerian@us.ibm.com>
The Decimal Floating Point C Library is free software; you can
redistribute it and/or modify it under the terms of the GNU Lesser
General Public License version 2.1.
The Decimal Floating Point C Library 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 Lesser General Public License version 2.1 for more details.
You should have received a copy of the GNU Lesser General Public
License version 2.1 along with the Decimal Floating Point C Library;
if not, write to the Free Software Foundation, Inc., 59 Temple Place,
Suite 330, Boston, MA 02111-1307 USA.
Please see libdfp/COPYING.txt for more information. */
#ifndef _DECIMAL_SIZE
# define _DECIMAL_SIZE 32
# include <decimal32.h>
#endif
#include <decContext.h>
#include <decNumber.h>
#include <math.h>
#include <ieee754r_private.h>
#include <decNumberMath.h>
#define FUNCTION_NAME frexp
#include <dfpmacro.h>
#include <numdigits.h>
DEC_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x, int *y)
{
/* GCC isn't smart enough to realize that the else block sets this in the
* FUNC_CONVERT_FROM_DN macro so simply initialize it to NaN to silence the
* warnings. */
DEC_TYPE result = DEC_NAN;
#if NUMDIGITS_SUPPORT==1
int digits, exponent;
if (FUNC_D (__isinf) (x) || FUNC_D (__isnan) (x))
return x+x;
// Given 3.1e0 is encoded as 31e-1 and we want .31e1
// We have 2 'digits'.
// Given 30.0e0 is encoded as 300e-1 and we want .300e2
// We have 3 'digits'.
// Given .003e0 is encoded as 3e3 and we want .3e-2
// We have 1 'digits'.
digits = FUNC_D (numdigits) (x);
// We have -1 exponent.
// We have -1 exponent.
// We have -3 exponent.
exponent = FUNC_D (getexp) (x);
*y = digits + exponent;
result = FUNC_D(setexp) (x, -digits);
//2 + (-1) = 1 0
//3 + (-1) = 2 0
//1 + (-3) = -2
#else
decNumber dn_x;
decContext context;
*y = 0;
FUNC_CONVERT_TO_DN(&x, &dn_x);
if (___decNumberIsNaN (&dn_x) || ___decNumberIsInfinite (&dn_x)
|| ___decNumberIsZero (&dn_x))
return x+x;
*y = dn_x.digits + dn_x.exponent;
dn_x.exponent = -dn_x.digits;
decContextDefault(&context, DEFAULT_CONTEXT);
FUNC_CONVERT_FROM_DN (&dn_x, &result, &context);
#endif
return result;
}
weak_alias (INTERNAL_FUNCTION_NAME, EXTERNAL_FUNCTION_NAME)
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