1  /* Complex cosine hyperbolic function for float types.
       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 <fenv.h>
      21  #include <math.h>
      22  #include <math_private.h>
      23  #include <math-underflow.h>
      24  #include <float.h>
      25  
      26  CFLOAT
      27  M_DECL_FUNC (__ccosh) (CFLOAT x)
      28  {
      29    CFLOAT retval;
      30    int rcls = fpclassify (__real__ x);
      31    int icls = fpclassify (__imag__ x);
      32  
      33    if (__glibc_likely (rcls >= FP_ZERO))
      34      {
      35        /* Real part is finite.  */
      36        if (__glibc_likely (icls >= FP_ZERO))
      37  	{
      38  	  /* Imaginary part is finite.  */
      39  	  const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2));
      40  	  FLOAT sinix, cosix;
      41  
      42  	  if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
      43  	    {
      44  	      M_SINCOS (__imag__ x, &sinix, &cosix);
      45  	    }
      46  	  else
      47  	    {
      48  	      sinix = __imag__ x;
      49  	      cosix = 1;
      50  	    }
      51  
      52  	  if (M_FABS (__real__ x) > t)
      53  	    {
      54  	      FLOAT exp_t = M_EXP (t);
      55  	      FLOAT rx = M_FABS (__real__ x);
      56  	      if (signbit (__real__ x))
      57  		sinix = -sinix;
      58  	      rx -= t;
      59  	      sinix *= exp_t / 2;
      60  	      cosix *= exp_t / 2;
      61  	      if (rx > t)
      62  		{
      63  		  rx -= t;
      64  		  sinix *= exp_t;
      65  		  cosix *= exp_t;
      66  		}
      67  	      if (rx > t)
      68  		{
      69  		  /* Overflow (original real part of x > 3t).  */
      70  		  __real__ retval = M_MAX * cosix;
      71  		  __imag__ retval = M_MAX * sinix;
      72  		}
      73  	      else
      74  		{
      75  		  FLOAT exp_val = M_EXP (rx);
      76  		  __real__ retval = exp_val * cosix;
      77  		  __imag__ retval = exp_val * sinix;
      78  		}
      79  	    }
      80  	  else
      81  	    {
      82  	      __real__ retval = M_COSH (__real__ x) * cosix;
      83  	      __imag__ retval = M_SINH (__real__ x) * sinix;
      84  	    }
      85  
      86  	  math_check_force_underflow_complex (retval);
      87  	}
      88        else
      89  	{
      90  	  __imag__ retval = __real__ x == 0 ? 0 : M_NAN;
      91  	  __real__ retval = __imag__ x - __imag__ x;
      92  	}
      93      }
      94    else if (rcls == FP_INFINITE)
      95      {
      96        /* Real part is infinite.  */
      97        if (__glibc_likely (icls > FP_ZERO))
      98  	{
      99  	  /* Imaginary part is finite.  */
     100  	  FLOAT sinix, cosix;
     101  
     102  	  if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
     103  	    {
     104  	      M_SINCOS (__imag__ x, &sinix, &cosix);
     105  	    }
     106  	  else
     107  	    {
     108  	      sinix = __imag__ x;
     109  	      cosix = 1;
     110  	    }
     111  
     112  	  __real__ retval = M_COPYSIGN (M_HUGE_VAL, cosix);
     113  	  __imag__ retval = (M_COPYSIGN (M_HUGE_VAL, sinix)
     114  			     * M_COPYSIGN (1, __real__ x));
     115  	}
     116        else if (icls == FP_ZERO)
     117  	{
     118  	  /* Imaginary part is 0.0.  */
     119  	  __real__ retval = M_HUGE_VAL;
     120  	  __imag__ retval = __imag__ x * M_COPYSIGN (1, __real__ x);
     121  	}
     122        else
     123  	{
     124  	  __real__ retval = M_HUGE_VAL;
     125  	  __imag__ retval = __imag__ x - __imag__ x;
     126  	}
     127      }
     128    else
     129      {
     130        __real__ retval = M_NAN;
     131        __imag__ retval = __imag__ x == 0 ? __imag__ x : M_NAN;
     132      }
     133  
     134    return retval;
     135  }
     136  
     137  declare_mgen_alias (__ccosh, ccosh);