math/s_cexp.c

   1 /* Return value of complex exponential function for double complex value.
   2    Copyright (C) 1997, 2011 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 #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 (__builtin_expect (rcls >= FP_ZERO, 1))
  35     {
  36       /* Real part is finite.  */
  37       if (__builtin_expect (icls >= FP_ZERO, 1))
  38         {
  39           /* Imaginary part is finite.  */
  40           double exp_val = __ieee754_exp (__real__ x);
  41           double sinix, cosix;
  42
  43           __sincos (__imag__ x, &sinix, &cosix);
  44
  45           if (isfinite (exp_val))
  46             {
  47               __real__ retval = exp_val * cosix;
  48               __imag__ retval = exp_val * sinix;
  49             }
  50           else
  51             {
  52               __real__ retval = __copysign (exp_val, cosix);
  53               __imag__ retval = __copysign (exp_val, sinix);
  54             }
  55         }
  56       else
  57         {
  58           /* If the imaginary part is +-inf or NaN and the real part
  59              is not +-inf the result is NaN + iNaN.  */
  60           __real__ retval = __nan ("");
  61           __imag__ retval = __nan ("");
  62
  63           feraiseexcept (FE_INVALID);
  64         }
  65     }
  66   else if (__builtin_expect (rcls == FP_INFINITE, 1))
  67     {
  68       /* Real part is infinite.  */
  69       if (__builtin_expect (icls >= FP_ZERO, 1))
  70         {
  71           /* Imaginary part is finite.  */
  72           double value = signbit (__real__ x) ? 0.0 : HUGE_VAL;
  73
  74           if (icls == FP_ZERO)
  75             {
  76               /* Imaginary part is 0.0.  */
  77               __real__ retval = value;
  78               __imag__ retval = __imag__ x;
  79             }
  80           else
  81             {
  82               double sinix, cosix;
  83
  84               __sincos (__imag__ x, &sinix, &cosix);
  85
  86               __real__ retval = __copysign (value, cosix);
  87               __imag__ retval = __copysign (value, sinix);
  88             }
  89         }
  90       else if (signbit (__real__ x) == 0)
  91         {
  92           __real__ retval = HUGE_VAL;
  93           __imag__ retval = __nan ("");
  94
  95           if (icls == FP_INFINITE)
  96             feraiseexcept (FE_INVALID);
  97         }
  98       else
  99         {
 100           __real__ retval = 0.0;
 101           __imag__ retval = __copysign (0.0, __imag__ x);
 102         }
 103     }
 104   else
 105     {
 106       /* If the real part is NaN the result is NaN + iNaN.  */
 107       __real__ retval = __nan ("");
 108       __imag__ retval = __nan ("");
 109
 110       if (rcls != FP_NAN || icls != FP_NAN)
 111         feraiseexcept (FE_INVALID);
 112     }
 113
 114   return retval;
 115 }
 116 weak_alias (__cexp, cexp)
 117 #ifdef NO_LONG_DOUBLE
 118 strong_alias (__cexp, __cexpl)
 119 weak_alias (__cexp, cexpl)
 120 #endif