math/s_ccosh.c

   1 /* Complex cosine hyperbole function for double.
   2    Copyright (C) 1997-2015 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    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <complex.h>
  21 #include <fenv.h>
  22 #include <math.h>
  23 #include <math_private.h>
  24 #include <float.h>
  25
  26 __complex__ double
  27 __ccosh (__complex__ double x)
  28 {
  29   __complex__ double 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) ((DBL_MAX_EXP - 1) * M_LN2);
  40           double sinix, cosix;
  41
  42           if (__glibc_likely (icls != FP_SUBNORMAL))
  43             {
  44               __sincos (__imag__ x, &sinix, &cosix);
  45             }
  46           else
  47             {
  48               sinix = __imag__ x;
  49               cosix = 1.0;
  50             }
  51
  52           if (fabs (__real__ x) > t)
  53             {
  54               double exp_t = __ieee754_exp (t);
  55               double rx = fabs (__real__ x);
  56               if (signbit (__real__ x))
  57                 sinix = -sinix;
  58               rx -= t;
  59               sinix *= exp_t / 2.0;
  60               cosix *= exp_t / 2.0;
  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 = DBL_MAX * cosix;
  71                   __imag__ retval = DBL_MAX * sinix;
  72                 }
  73               else
  74                 {
  75                   double exp_val = __ieee754_exp (rx);
  76                   __real__ retval = exp_val * cosix;
  77                   __imag__ retval = exp_val * sinix;
  78                 }
  79             }
  80           else
  81             {
  82               __real__ retval = __ieee754_cosh (__real__ x) * cosix;
  83               __imag__ retval = __ieee754_sinh (__real__ x) * sinix;
  84             }
  85
  86           if (fabs (__real__ retval) < DBL_MIN)
  87             {
  88               volatile double force_underflow
  89                 = __real__ retval * __real__ retval;
  90               (void) force_underflow;
  91             }
  92           if (fabs (__imag__ retval) < DBL_MIN)
  93             {
  94               volatile double force_underflow
  95                 = __imag__ retval * __imag__ retval;
  96               (void) force_underflow;
  97             }
  98         }
  99       else
 100         {
 101           __imag__ retval = __real__ x == 0.0 ? 0.0 : __nan ("");
 102           __real__ retval = __nan ("") + __nan ("");
 103
 104           if (icls == FP_INFINITE)
 105             feraiseexcept (FE_INVALID);
 106         }
 107     }
 108   else if (rcls == FP_INFINITE)
 109     {
 110       /* Real part is infinite.  */
 111       if (__glibc_likely (icls > FP_ZERO))
 112         {
 113           /* Imaginary part is finite.  */
 114           double sinix, cosix;
 115
 116           if (__glibc_likely (icls != FP_SUBNORMAL))
 117             {
 118               __sincos (__imag__ x, &sinix, &cosix);
 119             }
 120           else
 121             {
 122               sinix = __imag__ x;
 123               cosix = 1.0;
 124             }
 125
 126           __real__ retval = __copysign (HUGE_VAL, cosix);
 127           __imag__ retval = (__copysign (HUGE_VAL, sinix)
 128                              * __copysign (1.0, __real__ x));
 129         }
 130       else if (icls == FP_ZERO)
 131         {
 132           /* Imaginary part is 0.0.  */
 133           __real__ retval = HUGE_VAL;
 134           __imag__ retval = __imag__ x * __copysign (1.0, __real__ x);
 135         }
 136       else
 137         {
 138           /* The addition raises the invalid exception.  */
 139           __real__ retval = HUGE_VAL;
 140           __imag__ retval = __nan ("") + __nan ("");
 141
 142           if (icls == FP_INFINITE)
 143             feraiseexcept (FE_INVALID);
 144         }
 145     }
 146   else
 147     {
 148       __real__ retval = __nan ("");
 149       __imag__ retval = __imag__ x == 0.0 ? __imag__ x : __nan ("");
 150     }
 151
 152   return retval;
 153 }
 154 weak_alias (__ccosh, ccosh)
 155 #ifdef NO_LONG_DOUBLE
 156 strong_alias (__ccosh, __ccoshl)
 157 weak_alias (__ccosh, ccoshl)
 158 #endif