math/s_csinh.c

   1 /* Complex sine 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 __csinh (__complex__ double x)
  28 {
  29   __complex__ double retval;
  30   int negate = signbit (__real__ x);
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   __real__ x = fabs (__real__ x);
  35
  36   if (__builtin_expect (rcls >= FP_ZERO, 1))
  37     {
  38       /* Real part is finite.  */
  39       if (__builtin_expect (icls >= FP_ZERO, 1))
  40         {
  41           /* Imaginary part is finite.  */
  42           const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2);
  43           double sinix, cosix;
  44
  45           __sincos (__imag__ x, &sinix, &cosix);
  46
  47           if (fabs (__real__ x) > t)
  48             {
  49               double exp_t = __ieee754_exp (t);
  50               double rx = fabs (__real__ x);
  51               if (signbit (__real__ x))
  52                 cosix = -cosix;
  53               rx -= t;
  54               sinix *= exp_t / 2.0;
  55               cosix *= exp_t / 2.0;
  56               if (rx > t)
  57                 {
  58                   rx -= t;
  59                   sinix *= exp_t;
  60                   cosix *= exp_t;
  61                 }
  62               if (rx > t)
  63                 {
  64                   /* Overflow (original real part of x > 3t).  */
  65                   __real__ retval = DBL_MAX * cosix;
  66                   __imag__ retval = DBL_MAX * sinix;
  67                 }
  68               else
  69                 {
  70                   double exp_val = __ieee754_exp (rx);
  71                   __real__ retval = exp_val * cosix;
  72                   __imag__ retval = exp_val * sinix;
  73                 }
  74             }
  75           else
  76             {
  77               __real__ retval = __ieee754_sinh (__real__ x) * cosix;
  78               __imag__ retval = __ieee754_cosh (__real__ x) * sinix;
  79             }
  80
  81           if (negate)
  82             __real__ retval = -__real__ retval;
  83         }
  84       else
  85         {
  86           if (rcls == FP_ZERO)
  87             {
  88               /* Real part is 0.0.  */
  89               __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
  90               __imag__ retval = __nan ("") + __nan ("");
  91
  92               if (icls == FP_INFINITE)
  93                 feraiseexcept (FE_INVALID);
  94             }
  95           else
  96             {
  97               __real__ retval = __nan ("");
  98               __imag__ retval = __nan ("");
  99
 100               feraiseexcept (FE_INVALID);
 101             }
 102         }
 103     }
 104   else if (rcls == FP_INFINITE)
 105     {
 106       /* Real part is infinite.  */
 107       if (__builtin_expect (icls > FP_ZERO, 1))
 108         {
 109           /* Imaginary part is finite.  */
 110           double sinix, cosix;
 111
 112           __sincos (__imag__ x, &sinix, &cosix);
 113
 114           __real__ retval = __copysign (HUGE_VAL, cosix);
 115           __imag__ retval = __copysign (HUGE_VAL, sinix);
 116
 117           if (negate)
 118             __real__ retval = -__real__ retval;
 119         }
 120       else if (icls == FP_ZERO)
 121         {
 122           /* Imaginary part is 0.0.  */
 123           __real__ retval = negate ? -HUGE_VAL : HUGE_VAL;
 124           __imag__ retval = __imag__ x;
 125         }
 126       else
 127         {
 128           /* The addition raises the invalid exception.  */
 129           __real__ retval = HUGE_VAL;
 130           __imag__ retval = __nan ("") + __nan ("");
 131
 132           if (icls == FP_INFINITE)
 133             feraiseexcept (FE_INVALID);
 134         }
 135     }
 136   else
 137     {
 138       __real__ retval = __nan ("");
 139       __imag__ retval = __imag__ x == 0.0 ? __imag__ x : __nan ("");
 140     }
 141
 142   return retval;
 143 }
 144 weak_alias (__csinh, csinh)
 145 #ifdef NO_LONG_DOUBLE
 146 strong_alias (__csinh, __csinhl)
 147 weak_alias (__csinh, csinhl)
 148 #endif