libquadmath/math/cacosq.c

   1 /* Return cosine of a complex type.
   2    Copyright (C) 1997-2018 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 "quadmath-imp.h"
  21
  22 __complex128
  23 cacosq (__complex128 x)
  24 {
  25   __complex128 y;
  26   __complex128 res;
  27   int rcls = fpclassifyq (__real__ x);
  28   int icls = fpclassifyq (__imag__ x);
  29
  30   if (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE
  31       || (rcls == QUADFP_ZERO && icls == QUADFP_ZERO))
  32     {
  33       y = casinq (x);
  34
  35       __real__ res = (__float128) M_PI_2q - __real__ y;
  36       if (__real__ res == 0)
  37         __real__ res = 0;
  38       __imag__ res = -__imag__ y;
  39     }
  40   else
  41     {
  42       __real__ y = -__imag__ x;
  43       __imag__ y = __real__ x;
  44
  45       y = __quadmath_kernel_casinhq (y, 1);
  46
  47       __real__ res = __imag__ y;
  48       __imag__ res = __real__ y;
  49     }
  50
  51   return res;
  52 }