math/s_ccosh_template.c

   1 /* Complex cosine hyperbolic function for float types.
   2    Copyright (C) 1997-2020 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    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <complex.h>
  21 #include <fenv.h>
  22 #include <math.h>
  23 #include <math_private.h>
  24 #include <math-underflow.h>
  25 #include <float.h>
  26
  27 CFLOAT
  28 M_DECL_FUNC (__ccosh) (CFLOAT x)
  29 {
  30   CFLOAT retval;
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   if (__glibc_likely (rcls >= FP_ZERO))
  35     {
  36       /* Real part is finite.  */
  37       if (__glibc_likely (icls >= FP_ZERO))
  38         {
  39           /* Imaginary part is finite.  */
  40           const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2));
  41           FLOAT sinix, cosix;
  42
  43           if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
  44             {
  45               M_SINCOS (__imag__ x, &sinix, &cosix);
  46             }
  47           else
  48             {
  49               sinix = __imag__ x;
  50               cosix = 1;
  51             }
  52
  53           if (M_FABS (__real__ x) > t)
  54             {
  55               FLOAT exp_t = M_EXP (t);
  56               FLOAT rx = M_FABS (__real__ x);
  57               if (signbit (__real__ x))
  58                 sinix = -sinix;
  59               rx -= t;
  60               sinix *= exp_t / 2;
  61               cosix *= exp_t / 2;
  62               if (rx > t)
  63                 {
  64                   rx -= t;
  65                   sinix *= exp_t;
  66                   cosix *= exp_t;
  67                 }
  68               if (rx > t)
  69                 {
  70                   /* Overflow (original real part of x > 3t).  */
  71                   __real__ retval = M_MAX * cosix;
  72                   __imag__ retval = M_MAX * sinix;
  73                 }
  74               else
  75                 {
  76                   FLOAT exp_val = M_EXP (rx);
  77                   __real__ retval = exp_val * cosix;
  78                   __imag__ retval = exp_val * sinix;
  79                 }
  80             }
  81           else
  82             {
  83               __real__ retval = M_COSH (__real__ x) * cosix;
  84               __imag__ retval = M_SINH (__real__ x) * sinix;
  85             }
  86
  87           math_check_force_underflow_complex (retval);
  88         }
  89       else
  90         {
  91           __imag__ retval = __real__ x == 0 ? 0 : M_NAN;
  92           __real__ retval = __imag__ x - __imag__ x;
  93         }
  94     }
  95   else if (rcls == FP_INFINITE)
  96     {
  97       /* Real part is infinite.  */
  98       if (__glibc_likely (icls > FP_ZERO))
  99         {
 100           /* Imaginary part is finite.  */
 101           FLOAT sinix, cosix;
 102
 103           if (__glibc_likely (M_FABS (__imag__ x) > M_MIN))
 104             {
 105               M_SINCOS (__imag__ x, &sinix, &cosix);
 106             }
 107           else
 108             {
 109               sinix = __imag__ x;
 110               cosix = 1;
 111             }
 112
 113           __real__ retval = M_COPYSIGN (M_HUGE_VAL, cosix);
 114           __imag__ retval = (M_COPYSIGN (M_HUGE_VAL, sinix)
 115                              * M_COPYSIGN (1, __real__ x));
 116         }
 117       else if (icls == FP_ZERO)
 118         {
 119           /* Imaginary part is 0.0.  */
 120           __real__ retval = M_HUGE_VAL;
 121           __imag__ retval = __imag__ x * M_COPYSIGN (1, __real__ x);
 122         }
 123       else
 124         {
 125           __real__ retval = M_HUGE_VAL;
 126           __imag__ retval = __imag__ x - __imag__ x;
 127         }
 128     }
 129   else
 130     {
 131       __real__ retval = M_NAN;
 132       __imag__ retval = __imag__ x == 0 ? __imag__ x : M_NAN;
 133     }
 134
 135   return retval;
 136 }
 137
 138 declare_mgen_alias (__ccosh, ccosh);