math/s_cacos_template.c

   1 /* Return cosine of a complex type.
   2    Copyright (C) 1997-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <complex.h>
  20 #include <math.h>
  21
  22 CFLOAT
  23 M_DECL_FUNC (__cacos) (CFLOAT x)
  24 {
  25   CFLOAT y;
  26   CFLOAT res;
  27   int rcls = fpclassify (__real__ x);
  28   int icls = fpclassify (__imag__ x);
  29
  30   if (rcls <= FP_INFINITE || icls <= FP_INFINITE
  31       || (rcls == FP_ZERO && icls == FP_ZERO))
  32     {
  33       y = M_SUF (__casin) (x);
  34
  35       __real__ res = M_MLIT (M_PI_2) - __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 = M_SUF (__kernel_casinh) (y, 1);
  46
  47       __real__ res = __imag__ y;
  48       __imag__ res = __real__ y;
  49     }
  50
  51   return res;
  52 }
  53
  54 declare_mgen_alias (__cacos, cacos);