newlib/libm/complex/catanl.c

   1 /* $NetBSD: catanl.c,v 1.1 2014/10/10 00:48:18 christos Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2007 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software written by Stephen L. Moshier.
   8  * It is redistributed by the NetBSD Foundation by permission of the author.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <complex.h>
  33 #include <math.h>
  34 #include "cephes_subrl.h"
  35
  36 /* On platforms where long double is as wide as double.  */
  37 #ifdef _LDBL_EQ_DBL
  38 #ifdef __weak_alias
  39 __weak_alias(catanl, _catanl)
  40 #endif
  41
  42 long double complex
  43 catanl(long double complex z)
  44 {
  45         long double complex w;
  46         long double a, t, x, x2, y;
  47
  48         x = creall(z);
  49         y = cimagl(z);
  50
  51         if ((x == 0.0L) && (y > 1.0L))
  52                 goto ovrf;
  53
  54         x2 = x * x;
  55         a = 1.0L - x2 - (y * y);
  56
  57         t = 0.5L * atan2l(2.0L * x, a);
  58         w = _redupil(t);
  59
  60         t = y - 1.0L;
  61         a = x2 + (t * t);
  62         if (a == 0.0L)
  63                 goto ovrf;
  64
  65         t = y + 1.0L;
  66         a = (x2 + (t * t))/a;
  67         w = w + (0.25L * logl(a)) * I;
  68         return w;
  69
  70 ovrf:
  71 #if 0
  72         mtherr ("catanl", OVERFLOW);
  73 #endif
  74         w = HUGE_VALL + HUGE_VALL * I;
  75         return w;
  76 }
  77 #endif