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