math/s_cexp.c

   1 /* Return value of complex exponential function for double complex value.
   2    Copyright (C) 1997 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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <complex.h>
  22 #include <fenv.h>
  23 #include <math.h>
  24
  25 #include "math_private.h"
  26
  27
  28 __complex__ double
  29 __cexp (__complex__ double x)
  30 {
  31   __complex__ double retval;
  32   int rcls = fpclassify (__real__ x);
  33   int icls = fpclassify (__imag__ x);
  34
  35   if (rcls >= FP_ZERO)
  36     {
  37       /* Real part is finite.  */
  38       if (icls >= FP_ZERO)
  39         {
  40           /* Imaginary part is finite.  */
  41           double exp_val = __ieee754_exp (__real__ x);
  42           double sinix, cosix;
  43
  44           __sincos (__imag__ x, &sinix, &cosix);
  45
  46           if (isfinite (exp_val))
  47             {
  48               __real__ retval = exp_val * cosix;
  49               __imag__ retval = exp_val * sinix;
  50             }
  51           else
  52             {
  53               __real__ retval = __copysign (exp_val, cosix);
  54               __imag__ retval = __copysign (exp_val, sinix);
  55             }
  56         }
  57       else
  58         {
  59           /* If the imaginary part is +-inf or NaN and the real part
  60              is not +-inf the result is NaN + iNaN.  */
  61           __real__ retval = __nan ("");
  62           __imag__ retval = __nan ("");
  63
  64 #ifdef FE_INVALID
  65           feraiseexcept (FE_INVALID);
  66 #endif
  67         }
  68     }
  69   else if (rcls == FP_INFINITE)
  70     {
  71       /* Real part is infinite.  */
  72       if (icls >= FP_ZERO)
  73         {
  74           /* Imaginary part is finite.  */
  75           double value = signbit (__real__ x) ? 0.0 : HUGE_VAL;
  76
  77           if (icls == FP_ZERO)
  78             {
  79               /* Imaginary part is 0.0.  */
  80               __real__ retval = value;
  81               __imag__ retval = __imag__ x;
  82             }
  83           else
  84             {
  85               double sinix, cosix;
  86
  87               __sincos (__imag__ x, &sinix, &cosix);
  88
  89               __real__ retval = __copysign (value, cosix);
  90               __imag__ retval = __copysign (value, sinix);
  91             }
  92         }
  93       else if (signbit (__real__ x) == 0)
  94         {
  95           __real__ retval = HUGE_VAL;
  96           __imag__ retval = __nan ("");
  97
  98 #ifdef FE_INVALID
  99           if (icls == FP_INFINITE)
 100             feraiseexcept (FE_INVALID);
 101 #endif
 102         }
 103       else
 104         {
 105           __real__ retval = 0.0;
 106           __imag__ retval = __copysign (0.0, __imag__ x);
 107         }
 108     }
 109   else
 110     {
 111       /* If the real part is NaN the result is NaN + iNaN.  */
 112       __real__ retval = __nan ("");
 113       __imag__ retval = __nan ("");
 114
 115 #ifdef FE_INVALID
 116       if (rcls != FP_NAN || icls != FP_NAN)
 117         feraiseexcept (FE_INVALID);
 118 #endif
 119     }
 120
 121   return retval;
 122 }
 123 weak_alias (__cexp, cexp)
 124 #ifdef NO_LONG_DOUBLE
 125 strong_alias (__cexp, __cexpl)
 126 weak_alias (__cexp, cexpl)
 127 #endif