glibc/math/s_ctanhl.c
2012-02-09 23:18:22 +00:00

77 lines
2.0 KiB
C

/* Complex hyperbole tangent for long double.
Copyright (C) 1997, 2005, 2011 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, see
<http://www.gnu.org/licenses/>. */
#include <complex.h>
#include <fenv.h>
#include <math.h>
#include <math_private.h>
__complex__ long double
__ctanhl (__complex__ long double x)
{
__complex__ long double res;
if (__builtin_expect (!isfinite (__real__ x) || !isfinite (__imag__ x), 0))
{
if (__isinf_nsl (__real__ x))
{
__real__ res = __copysignl (1.0, __real__ x);
__imag__ res = __copysignl (0.0, __imag__ x);
}
else if (__imag__ x == 0.0)
{
res = x;
}
else
{
__real__ res = __nanl ("");
__imag__ res = __nanl ("");
if (__isinf_nsl (__imag__ x))
feraiseexcept (FE_INVALID);
}
}
else
{
long double sin2ix, cos2ix;
long double den;
__sincosl (2.0 * __imag__ x, &sin2ix, &cos2ix);
den = (__ieee754_coshl (2.0 * __real__ x) + cos2ix);
if (den == 0.0L)
{
__complex__ long double ez = __cexpl (x);
__complex__ long double emz = __cexpl (-x);
res = (ez - emz) / (ez + emz);
}
else
{
__real__ res = __ieee754_sinhl (2.0 * __real__ x) / den;
__imag__ res = sin2ix / den;
}
}
return res;
}
weak_alias (__ctanhl, ctanhl)