Retro68/gcc/newlib/libm/complex/catanf.c
2012-03-27 01:51:53 +02:00

80 lines
2.3 KiB
C

/* $NetBSD: catanf.c,v 1.1 2007/08/20 16:01:32 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>
*/
#include <complex.h>
#include <math.h>
#include "cephes_subrf.h"
#ifdef __weak_alias
__weak_alias(catanf, _catanf)
#endif
float complex
catanf(float complex z)
{
float complex w;
float a, t, x, x2, y;
x = crealf(z);
y = cimagf(z);
if ((x == 0.0f) && (y > 1.0f))
goto ovrf;
x2 = x * x;
a = 1.0f - x2 - (y * y);
if (a == 0.0f)
goto ovrf;
t = 0.5f * atan2f(2.0f * x, a);
w = _redupif(t);
t = y - 1.0f;
a = x2 + (t * t);
if (a == 0.0f)
goto ovrf;
t = y + 1.0f;
a = (x2 + (t * t))/a;
w = w + (0.25f * logf(a)) * I;
return w;
ovrf:
#if 0
mtherr ("catan", OVERFLOW);
#endif
w = HUGE_VALF + HUGE_VALF * I;
return w;
}