math/s_csinh.c

   1 /* Complex sine hyperbole function for double.
   2    Copyright (C) 1997-2013 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           if (__builtin_expect (icls != FP_SUBNORMAL, 1))
  46             {
  47               __sincos (__imag__ x, &sinix, &cosix);
  48             }
  49           else
  50             {
  51               sinix = __imag__ x;
  52               cosix = 1.0;
  53             }
  54
  55           if (fabs (__real__ x) > t)
  56             {
  57               double exp_t = __ieee754_exp (t);
  58               double rx = fabs (__real__ x);
  59               if (signbit (__real__ x))
  60                 cosix = -cosix;
  61               rx -= t;
  62               sinix *= exp_t / 2.0;
  63               cosix *= exp_t / 2.0;
  64               if (rx > t)
  65                 {
  66                   rx -= t;
  67                   sinix *= exp_t;
  68                   cosix *= exp_t;
  69                 }
  70               if (rx > t)
  71                 {
  72                   /* Overflow (original real part of x > 3t).  */
  73                   __real__ retval = DBL_MAX * cosix;
  74                   __imag__ retval = DBL_MAX * sinix;
  75                 }
  76               else
  77                 {
  78                   double exp_val = __ieee754_exp (rx);
  79                   __real__ retval = exp_val * cosix;
  80                   __imag__ retval = exp_val * sinix;
  81                 }
  82             }
  83           else
  84             {
  85               __real__ retval = __ieee754_sinh (__real__ x) * cosix;
  86               __imag__ retval = __ieee754_cosh (__real__ x) * sinix;
  87             }
  88
  89           if (negate)
  90             __real__ retval = -__real__ retval;
  91         }
  92       else
  93         {
  94           if (rcls == FP_ZERO)
  95             {
  96               /* Real part is 0.0.  */
  97               __real__ retval = __copysign (0.0, negate ? -1.0 : 1.0);
  98               __imag__ retval = __nan ("") + __nan ("");
  99
 100               if (icls == FP_INFINITE)
 101                 feraiseexcept (FE_INVALID);
 102             }
 103           else
 104             {
 105               __real__ retval = __nan ("");
 106               __imag__ retval = __nan ("");
 107
 108               feraiseexcept (FE_INVALID);
 109             }
 110         }
 111     }
 112   else if (rcls == FP_INFINITE)
 113     {
 114       /* Real part is infinite.  */
 115       if (__builtin_expect (icls > FP_ZERO, 1))
 116         {
 117           /* Imaginary part is finite.  */
 118           double sinix, cosix;
 119
 120           if (__builtin_expect (icls != FP_SUBNORMAL, 1))
 121             {
 122               __sincos (__imag__ x, &sinix, &cosix);
 123             }
 124           else
 125             {
 126               sinix = __imag__ x;
 127               cosix = 1.0;
 128             }
 129
 130           __real__ retval = __copysign (HUGE_VAL, cosix);
 131           __imag__ retval = __copysign (HUGE_VAL, sinix);
 132
 133           if (negate)
 134             __real__ retval = -__real__ retval;
 135         }
 136       else if (icls == FP_ZERO)
 137         {
 138           /* Imaginary part is 0.0.  */
 139           __real__ retval = negate ? -HUGE_VAL : HUGE_VAL;
 140           __imag__ retval = __imag__ x;
 141         }
 142       else
 143         {
 144           /* The addition raises the invalid exception.  */
 145           __real__ retval = HUGE_VAL;
 146           __imag__ retval = __nan ("") + __nan ("");
 147
 148           if (icls == FP_INFINITE)
 149             feraiseexcept (FE_INVALID);
 150         }
 151     }
 152   else
 153     {
 154       __real__ retval = __nan ("");
 155       __imag__ retval = __imag__ x == 0.0 ? __imag__ x : __nan ("");
 156     }
 157
 158   return retval;
 159 }
 160 weak_alias (__csinh, csinh)
 161 #ifdef NO_LONG_DOUBLE
 162 strong_alias (__csinh, __csinhl)
 163 weak_alias (__csinh, csinhl)
 164 #endif