1/* Return arc hyperbole tangent for __float128 value.
2 Copyright (C) 1997, 1998 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
20
21#include "quadmath-imp.h"
22
23
24__complex128
25catanhq (__complex128 x)
26{
27 __complex128 res;
28 int rcls = fpclassifyq (__real__ x);
29 int icls = fpclassifyq (__imag__ x);
30
31 if (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE)
32 {
33 if (icls == QUADFP_INFINITE)
34 {
35 __real__ res = copysignq (0.0, __real__ x);
36 __imag__ res = copysignq (M_PI_2q, __imag__ x);
37 }
38 else if (rcls == QUADFP_INFINITE || rcls == QUADFP_ZERO)
39 {
40 __real__ res = copysignq (0.0, __real__ x);
41 if (icls >= QUADFP_ZERO)
42 __imag__ res = copysignq (M_PI_2q, __imag__ x);
43 else
44 __imag__ res = nanq ("");
45 }
46 else
47 {
48 __real__ res = nanq ("");
49 __imag__ res = nanq ("");
50 }
51 }
52 else if (rcls == QUADFP_ZERO && icls == QUADFP_ZERO)
53 {
54 res = x;
55 }
56 else
57 {
58 __float128 i2, num, den;
59
60 i2 = __imag__ x * __imag__ x;
61
62 num = 1.0 + __real__ x;
63 num = i2 + num * num;
64
65 den = 1.0 - __real__ x;
66 den = i2 + den * den;
67
68 __real__ res = 0.25 * (logq (num) - logq (den));
69
70 den = 1 - __real__ x * __real__ x - i2;
71
72 __imag__ res = 0.5 * atan2q (2.0 * __imag__ x, den);
73 }
74
75 return res;
76}
77