math/s_ccosh.c

   1 /* Complex cosine hyperbole function for double.
   2    Copyright (C) 1997-2012 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 (__builtin_expect (rcls >= FP_ZERO, 1))
  34     {
  35       /* Real part is finite.  */
  36       if (__builtin_expect (icls >= FP_ZERO, 1))
  37         {
  38           /* Imaginary part is finite.  */
  39           const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2);
  40           double sinix, cosix;
  41
  42           __sincos (__imag__ x, &sinix, &cosix);
  43
  44           if (fabs (__real__ x) > t)
  45             {
  46               double exp_t = __ieee754_exp (t);
  47               double rx = fabs (__real__ x);
  48               if (signbit (__real__ x))
  49                 sinix = -sinix;
  50               rx -= t;
  51               sinix *= exp_t / 2.0;
  52               cosix *= exp_t / 2.0;
  53               if (rx > t)
  54                 {
  55                   rx -= t;
  56                   sinix *= exp_t;
  57                   cosix *= exp_t;
  58                 }
  59               if (rx > t)
  60                 {
  61                   /* Overflow (original real part of x > 3t).  */
  62                   __real__ retval = DBL_MAX * cosix;
  63                   __imag__ retval = DBL_MAX * sinix;
  64                 }
  65               else
  66                 {
  67                   double exp_val = __ieee754_exp (rx);
  68                   __real__ retval = exp_val * cosix;
  69                   __imag__ retval = exp_val * sinix;
  70                 }
  71             }
  72           else
  73             {
  74               __real__ retval = __ieee754_cosh (__real__ x) * cosix;
  75               __imag__ retval = __ieee754_sinh (__real__ x) * sinix;
  76             }
  77         }
  78       else
  79         {
  80           __imag__ retval = __real__ x == 0.0 ? 0.0 : __nan ("");
  81           __real__ retval = __nan ("") + __nan ("");
  82
  83           if (icls == FP_INFINITE)
  84             feraiseexcept (FE_INVALID);
  85         }
  86     }
  87   else if (rcls == FP_INFINITE)
  88     {
  89       /* Real part is infinite.  */
  90       if (__builtin_expect (icls > FP_ZERO, 1))
  91         {
  92           /* Imaginary part is finite.  */
  93           double sinix, cosix;
  94
  95           __sincos (__imag__ x, &sinix, &cosix);
  96
  97           __real__ retval = __copysign (HUGE_VAL, cosix);
  98           __imag__ retval = (__copysign (HUGE_VAL, sinix)
  99                              * __copysign (1.0, __real__ x));
 100         }
 101       else if (icls == FP_ZERO)
 102         {
 103           /* Imaginary part is 0.0.  */
 104           __real__ retval = HUGE_VAL;
 105           __imag__ retval = __imag__ x * __copysign (1.0, __real__ x);
 106         }
 107       else
 108         {
 109           /* The addition raises the invalid exception.  */
 110           __real__ retval = HUGE_VAL;
 111           __imag__ retval = __nan ("") + __nan ("");
 112
 113           if (icls == FP_INFINITE)
 114             feraiseexcept (FE_INVALID);
 115         }
 116     }
 117   else
 118     {
 119       __real__ retval = __nan ("");
 120       __imag__ retval = __imag__ x == 0.0 ? __imag__ x : __nan ("");
 121     }
 122
 123   return retval;
 124 }
 125 weak_alias (__ccosh, ccosh)
 126 #ifdef NO_LONG_DOUBLE
 127 strong_alias (__ccosh, __ccoshl)
 128 weak_alias (__ccosh, ccoshl)
 129 #endif