math/s_casinh.c

   1 /* Return arc hyperbole sine for double value.
   2    Copyright (C) 1997-2015 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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <complex.h>
  21 #include <math.h>
  22 #include <math_private.h>
  23
  24 __complex__ double
  25 __casinh (__complex__ double x)
  26 {
  27   __complex__ double res;
  28   int rcls = fpclassify (__real__ x);
  29   int icls = fpclassify (__imag__ x);
  30
  31   if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
  32     {
  33       if (icls == FP_INFINITE)
  34         {
  35           __real__ res = __copysign (HUGE_VAL, __real__ x);
  36
  37           if (rcls == FP_NAN)
  38             __imag__ res = __nan ("");
  39           else
  40             __imag__ res = __copysign (rcls >= FP_ZERO ? M_PI_2 : M_PI_4,
  41                                        __imag__ x);
  42         }
  43       else if (rcls <= FP_INFINITE)
  44         {
  45           __real__ res = __real__ x;
  46           if ((rcls == FP_INFINITE && icls >= FP_ZERO)
  47               || (rcls == FP_NAN && icls == FP_ZERO))
  48             __imag__ res = __copysign (0.0, __imag__ x);
  49           else
  50             __imag__ res = __nan ("");
  51         }
  52       else
  53         {
  54           __real__ res = __nan ("");
  55           __imag__ res = __nan ("");
  56         }
  57     }
  58   else if (rcls == FP_ZERO && icls == FP_ZERO)
  59     {
  60       res = x;
  61     }
  62   else
  63     {
  64       res = __kernel_casinh (x, 0);
  65     }
  66
  67   return res;
  68 }
  69 weak_alias (__casinh, casinh)
  70 #ifdef NO_LONG_DOUBLE
  71 strong_alias (__casinh, __casinhl)
  72 weak_alias (__casinh, casinhl)
  73 #endif