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/* $NetBSD: cacos.c,v 1.1 2007/08/20 16:01:30 drochner Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software written by Stephen L. Moshier.
* It is redistributed by the NetBSD Foundation by permission of the author.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* imported and modified include for newlib 2010/10/03
* Marco Atzeri <marco_atzeri@yahoo.it>
*/
/*
FUNCTION
<<cacos>>, <<cacosf>>---complex arc cosine
INDEX
cacos
INDEX
cacosf
ANSI_SYNOPSIS
#include <complex.h>
double complex cacos(double complex <[z]>);
float complex cacosf(float complex <[z]>);
DESCRIPTION
These functions compute the complex arc cosine of <[z]>,
with branch cuts outside the interval [-1, +1] along the real axis.
<<cacosf>> is identical to <<cacos>>, except that it performs
its calculations on <<floats complex>>.
RETURNS
@ifnottex
These functions return the complex arc cosine value, in the range
of a strip mathematically unbounded along the imaginary axis
and in the interval [0, pi] along the real axis.
@end ifnottex
@tex
These functions return the complex arc cosine value, in the range
of a strip mathematically unbounded along the imaginary axis
and in the interval [<<0>>, $\pi$] along the real axis.
@end tex
PORTABILITY
<<cacos>> and <<cacosf>> are ISO C99
QUICKREF
<<cacos>> and <<cacosf>> are ISO C99
*/
#include <complex.h>
#include <math.h>
double complex
cacos(double complex z)
{
double complex w;
/* FIXME: The original NetBSD code results in an ICE when trying to
build this function on ARM/Thumb using gcc 4.5.1. For now we use
a hopefully temporary workaround. */
#if 0
w = casin(z);
w = (M_PI_2 - creal(w)) - cimag(w) * I;
#else
double complex tmp0, tmp1;
tmp0 = casin(z);
tmp1 = M_PI_2 - creal(tmp0);
w = tmp1 - (cimag(tmp0) * I);
#endif
return w;
}
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