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asinhd32.c
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asinhd32.c
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/* Returns the hyperbolic arc sine of a _Decimal32 type argument
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): Pete Eberlein <[email protected]>
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., 51 Franklin
Street, Fifth Floor, Boston, MA 02110-1301 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 <decNumberMath.h>
#define FUNCTION_NAME asinh
#include <dfpmacro.h>
DEC_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x)
{
decContext context;
decNumber dn_result;
DEC_TYPE result, one;
decNumber dn_x, dn_one;
one = DFP_CONSTANT(1.0);
FUNC_CONVERT_TO_DN (&one, &dn_one);
FUNC_CONVERT_TO_DN (&x, &dn_x);
if (decNumberIsNaN (&dn_x) || decNumberIsZero (&dn_x)
|| decNumberIsInfinite (&dn_x))
{
return x + x;
}
decContextDefault (&context, DEFAULT_CONTEXT);
/* using trig identity: acosh(x) = log(x+sqrt(x*x-1)) */
decNumberMultiply (&dn_result, &dn_x, &dn_x, &context);
decNumberAdd (&dn_result, &dn_result, &dn_one, &context);
decNumberSquareRoot (&dn_result, &dn_result, &context);
decNumberAdd (&dn_result, &dn_result, &dn_x, &context);
decNumberLn (&dn_result, &dn_result, &context);
FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);
return result;
}
weak_alias (INTERNAL_FUNCTION_NAME, EXTERNAL_FUNCTION_NAME)