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/* Returns the next representable neighbor of x in the direction of y
Copyright (C) 2006 IBM Corporation.
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 dfp/COPYING.txt for more information. */
#ifndef _DECIMAL_SIZE
/* Always include this since we need a _Decimal128 converted to a decNumber */
# include <decimal128.h>
# include <dfptypeconv128.h>
# include <decimal32.h>
# define _DECIMAL_SIZE 32
#endif
#include <decContext.h>
#include <decNumber.h>
#include <math.h>
#include <errno.h>
#include <float.h>
#define FUNCTION_NAME nexttoward
#include <dfpmacro.h>
DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x, _Decimal128 y)
{
decContext context;
decNumber dn_result;
DEC_TYPE result;
DEC_TYPE epsilon;
decNumber dn_x;
decNumber dn_y;
decNumber dn_epsilon;
/* int comparison; */
FUNC_CONVERT_TO_DN(&x, &dn_x);
__DECIMAL_TO_DECNUMBER(&y, &dn_y, 128);
/* Early exit for nan's */
if (___decNumberIsNaN(&dn_x))
return x;
if (___decNumberIsNaN(&dn_y))
return y;
/*comparison = ___decCompare(&dn_x, &dn_y); */
/* Early exit for equal values */
/*if (comparison == 0) */
if (x==y)
return x;
epsilon = DFP_EPSILON;
FUNC_CONVERT_TO_DN(&epsilon, &dn_epsilon);
dn_epsilon.exponent += dn_x.digits+dn_x.exponent-1;
___decContextDefault(&context, DEFAULT_CONTEXT);
/*if (comparison > 0)*/
if (x>y)
___decNumberSubtract(&dn_result,&dn_x,&dn_epsilon,&context);
else
___decNumberAdd(&dn_result,&dn_x,&dn_epsilon,&context);
FUNC_CONVERT_FROM_DN(&dn_result, &result, &context);
if (context.status & DEC_Overflow)
DFP_EXCEPT (FE_OVERFLOW);
return result;
}
DEC_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x, _Decimal128 y)
{
DEC_TYPE z = IEEE_FUNCTION_NAME (x, y);
#ifndef _IEEE_LIBDFP
if (_LIB_VERSION == _IEEE_) return z;
if (!FUNC_D(__finite) (z) && FUNC_D(__finite) (x))
DFP_ERRNO (ERANGE);
/* TODO: Handle underflow */
#endif
return z;
}
weak_alias (INTERNAL_FUNCTION_NAME, EXTERNAL_FUNCTION_NAME)
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