newlib-cygwin/newlib/libc/sys/linux/cmath/s_cexp.c

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/* 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