source: trunk/libs/newlib/src/newlib/libc/sys/linux/cmath/s_cexp.c

/* Return value of complex exponential function for double complex value.
   Copyright (C) 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <complex.h>
#include <fenv.h>
#include <math.h>

#include "math_private.h"


__complex__ double
__cexp (__complex__ double x)
{
  __complex__ double retval;
  int rcls = fpclassify (__real__ x);
  int icls = fpclassify (__imag__ x);

  if (rcls >= FP_ZERO)
    {
      /* Real part is finite.  */
      if (icls >= FP_ZERO)
        {
          /* Imaginary part is finite.  */
          double exp_val = __ieee754_exp (__real__ x);
          double sinix, cosix;

          __sincos (__imag__ x, &sinix, &cosix);

          if (isfinite (exp_val))
            {
              __real__ retval = exp_val * cosix;
              __imag__ retval = exp_val * sinix;
            }
          else
            {
              __real__ retval = __copysign (exp_val, cosix);
              __imag__ retval = __copysign (exp_val, sinix);
            }
        }
      else
        {
          /* If the imaginary part is +-inf or NaN and the real part
             is not +-inf the result is NaN + iNaN.  */
          __real__ retval = __nan ("");
          __imag__ retval = __nan ("");

#ifdef FE_INVALID
          feraiseexcept (FE_INVALID);
#endif
        }
    }
  else if (rcls == FP_INFINITE)
    {
      /* Real part is infinite.  */
      if (icls >= FP_ZERO)
        {
          /* Imaginary part is finite.  */
          double value = signbit (__real__ x) ? 0.0 : HUGE_VAL;

          if (icls == FP_ZERO)
            {
              /* Imaginary part is 0.0.  */
              __real__ retval = value;
              __imag__ retval = __imag__ x;
            }
          else
            {
              double sinix, cosix;

              __sincos (__imag__ x, &sinix, &cosix);

              __real__ retval = __copysign (value, cosix);
              __imag__ retval = __copysign (value, sinix);
            }
        }
      else if (signbit (__real__ x) == 0)
        {
          __real__ retval = HUGE_VAL;
          __imag__ retval = __nan ("");

#ifdef FE_INVALID
          if (icls == FP_INFINITE)
            feraiseexcept (FE_INVALID);
#endif
        }
      else
        {
          __real__ retval = 0.0;
          __imag__ retval = __copysign (0.0, __imag__ x);
        }
    }
  else
    {
      /* If the real part is NaN the result is NaN + iNaN.  */
      __real__ retval = __nan ("");
      __imag__ retval = __nan ("");

#ifdef FE_INVALID
      if (rcls != FP_NAN || icls != FP_NAN)
        feraiseexcept (FE_INVALID);
#endif
    }

  return retval;
}
weak_alias (__cexp, cexp)
#ifdef NO_LONG_DOUBLE
strong_alias (__cexp, __cexpl)
weak_alias (__cexp, cexpl)
#endif