math/s_ccosh_template.c

   1 /* Complex cosine hyperbolic function for float types.
   2    Copyright (C) 1997-2022 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);