sysdeps/libm-ieee754/s_cexp.c

   1 /* Return value of complex exponential function for float 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 Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <complex.h>
  22 #include <math.h>
  23
  24
  25 __complex__ double
  26 __cexp (__complex__ double x)
  27 {
  28   __complex__ double retval;
  29
  30   if (isfinite (__real__ x))
  31     {
  32       if (isfinite (__imag__ x))
  33         {
  34           double exp_val = __exp (__real__ x);
  35
  36           if (isfinite (exp_val))
  37             {
  38               __real__ retval = exp_val * __cos (__imag__ x);
  39               __imag__ retval = exp_val * __sin (__imag__ x);
  40             }
  41           else
  42             {
  43               __real__ retval = __copysign (exp_val, __cos (__imag__ x));
  44               __imag__ retval = __copysign (exp_val, __sin (__imag__ x));
  45             }
  46         }
  47       else
  48         {
  49           /* If the imaginary part is +-inf or NaN and the real part
  50              is not +-inf the result is NaN + iNaN.  */
  51           __real__ retval = __nan ("");
  52           __imag__ retval = __nan ("");
  53         }
  54     }
  55   else if (__isinf (__real__ x))
  56     {
  57       if (isfinite (__imag__ x))
  58         {
  59           double value = signbit (__real__ x) ? 0.0 : HUGE_VAL;
  60
  61           if (__imag__ x == 0.0)
  62             {
  63               __real__ retval = value;
  64               __imag__ retval = __imag__ x;
  65             }
  66           else
  67             {
  68               __real__ retval = __copysign (value, __cos (__imag__ x));
  69               __imag__ retval = __copysign (value, __sin (__imag__ x));
  70             }
  71         }
  72       else if (signbit (__real__ x) == 0)
  73         {
  74           __real__ retval = HUGE_VAL;
  75           __imag__ retval = __nan ("");
  76         }
  77       else
  78         {
  79           __real__ retval = 0.0;
  80           __imag__ retval = __copysign (0.0, __imag__ x);
  81         }
  82     }
  83   else
  84     {
  85       /* If the real part is NaN the result is NaN + iNaN.  */
  86       __real__ retval = __nan ("");
  87       __imag__ retval = __nan ("");
  88     }
  89
  90   return retval;
  91 }
  92 weak_alias (__cexp, cexp)
  93 #ifdef NO_LONG_DOUBLE
  94 strong_alias (__cexp, __cexpl)
  95 weak_alias (__cexp, cexpl)
  96 #endif