sysdeps/libm-ieee754/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 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 #include "math_private.h"
  25
  26
  27 __complex__ double
  28 __cexp (__complex__ double x)
  29 {
  30   __complex__ double retval;
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   if (rcls >= FP_ZERO)
  35     {
  36       /* Real part is finite.  */
  37       if (icls >= FP_ZERO)
  38         {
  39           /* Imaginary part is finite.  */
  40           double exp_val = __ieee754_exp (__real__ x);
  41
  42           if (isfinite (exp_val))
  43             {
  44               __real__ retval = exp_val * __cos (__imag__ x);
  45               __imag__ retval = exp_val * __sin (__imag__ x);
  46             }
  47           else
  48             {
  49               __real__ retval = __copysign (exp_val, __cos (__imag__ x));
  50               __imag__ retval = __copysign (exp_val, __sin (__imag__ x));
  51             }
  52         }
  53       else
  54         {
  55           /* If the imaginary part is +-inf or NaN and the real part
  56              is not +-inf the result is NaN + iNaN.  */
  57           __real__ retval = __nan ("");
  58           __imag__ retval = __nan ("");
  59         }
  60     }
  61   else if (rcls == FP_INFINITE)
  62     {
  63       /* Real part is infinite.  */
  64       if (icls >= FP_ZERO)
  65         {
  66           /* Imaginary part is finite.  */
  67           double value = signbit (__real__ x) ? 0.0 : HUGE_VAL;
  68
  69           if (icls == FP_ZERO)
  70             {
  71               /* Imaginary part is 0.0.  */
  72               __real__ retval = value;
  73               __imag__ retval = __imag__ x;
  74             }
  75           else
  76             {
  77               __real__ retval = __copysign (value, __cos (__imag__ x));
  78               __imag__ retval = __copysign (value, __sin (__imag__ x));
  79             }
  80         }
  81       else if (signbit (__real__ x) == 0)
  82         {
  83           __real__ retval = HUGE_VAL;
  84           __imag__ retval = __nan ("");
  85         }
  86       else
  87         {
  88           __real__ retval = 0.0;
  89           __imag__ retval = __copysign (0.0, __imag__ x);
  90         }
  91     }
  92   else
  93     {
  94       /* If the real part is NaN the result is NaN + iNaN.  */
  95       __real__ retval = __nan ("");
  96       __imag__ retval = __nan ("");
  97     }
  98
  99   return retval;
 100 }
 101 weak_alias (__cexp, cexp)
 102 #ifdef NO_LONG_DOUBLE
 103 strong_alias (__cexp, __cexpl)
 104 weak_alias (__cexp, cexpl)
 105 #endif