11.1Schristos/* $NetBSD: catanl.c,v 1.1 2014/10/10 00:48:18 christos Exp $ */
21.1Schristos
31.1Schristos/*-
41.1Schristos * Copyright (c) 2007 The NetBSD Foundation, Inc.
51.1Schristos * All rights reserved.
61.1Schristos *
71.1Schristos * This code is derived from software written by Stephen L. Moshier.
81.1Schristos * It is redistributed by the NetBSD Foundation by permission of the author.
91.1Schristos *
101.1Schristos * Redistribution and use in source and binary forms, with or without
111.1Schristos * modification, are permitted provided that the following conditions
121.1Schristos * are met:
131.1Schristos * 1. Redistributions of source code must retain the above copyright
141.1Schristos *    notice, this list of conditions and the following disclaimer.
151.1Schristos * 2. Redistributions in binary form must reproduce the above copyright
161.1Schristos *    notice, this list of conditions and the following disclaimer in the
171.1Schristos *    documentation and/or other materials provided with the distribution.
181.1Schristos *
191.1Schristos * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.1Schristos * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.1Schristos * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.1Schristos * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.1Schristos * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.1Schristos * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.1Schristos * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.1Schristos * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.1Schristos * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.1Schristos * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.1Schristos * POSSIBILITY OF SUCH DAMAGE.
301.1Schristos */
311.1Schristos
321.1Schristos#include "../src/namespace.h"
331.1Schristos#include <complex.h>
341.1Schristos#include <math.h>
351.1Schristos#include <float.h>
361.1Schristos#include "cephes_subrl.h"
371.1Schristos
381.1Schristos#ifdef __weak_alias
391.1Schristos__weak_alias(catanl, _catanl)
401.1Schristos#endif
411.1Schristos
421.1Schristos#define MAXNUM LDBL_MAX
431.1Schristos
441.1Schristoslong double complex
451.1Schristoscatanl(long double complex z)
461.1Schristos{
471.1Schristos	long double complex w;
481.1Schristos	long double a, t, x, x2, y;
491.1Schristos
501.1Schristos	x = creall(z);
511.1Schristos	y = cimagl(z);
521.1Schristos
531.1Schristos	if ((x == 0.0L) && (y > 1.0L))
541.1Schristos		goto ovrf;
551.1Schristos
561.1Schristos	x2 = x * x;
571.1Schristos	a = 1.0L - x2 - (y * y);
581.1Schristos	if (a == 0.0)
591.1Schristos		goto ovrf;
601.1Schristos
611.1Schristos	t = 0.5L * atan2l(2.0L * x, a);
621.1Schristos	w = _redupil(t);
631.1Schristos
641.1Schristos	t = y - 1.0L;
651.1Schristos	a = x2 + (t * t);
661.1Schristos	if (a == 0.0L)
671.1Schristos		goto ovrf;
681.1Schristos
691.1Schristos	t = y + 1.0L;
701.1Schristos	a = (x2 + (t * t))/a;
711.1Schristos	w = w + (0.25L * logl(a)) * I;
721.1Schristos	return w;
731.1Schristos
741.1Schristosovrf:
751.1Schristos#if 0
761.1Schristos	mtherr ("catanl", OVERFLOW);
771.1Schristos#endif
781.1Schristos	w = MAXNUM + MAXNUM * I;
791.1Schristos	return w;
801.1Schristos}
81