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/* Returns the next representable neighbor of x in the direction of y
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
# include <decimal32.h>
# define _DECIMAL_SIZE 32
#endif
#include <decContext.h>
#include <decNumber.h>
#include <math.h>
#include <float.h>
#include <errno.h>
#include <ieee754r_private.h>
#define FUNCTION_NAME nextafter
#include <dfpmacro.h>
static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x, DEC_TYPE 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);
FUNC_CONVERT_TO_DN (&y, &dn_y);
/* Early exit for nan's */
if (decNumberIsNaN (&dn_x))
return x+x;
if (decNumberIsNaN (&dn_y))
return y+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, DEC_TYPE y)
{
DEC_TYPE z = IEEE_FUNCTION_NAME (x, y);
if (!FUNC_D(__isfinite) (z) && FUNC_D(__isfinite) (x))
DFP_ERRNO (ERANGE);
/* TODO: Handle underflow here */
return z;
}
weak_alias (INTERNAL_FUNCTION_NAME, EXTERNAL_FUNCTION_NAME)
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