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);