glibc/math/s_catanhl.c

84 lines
2.3 KiB
C

/* Return arc hyperbole tangent for long double value.
Copyright (C) 1997-2013 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 <math.h>
#include <math_private.h>
__complex__ long double
__catanhl (__complex__ long double x)
{
__complex__ long double res;
int rcls = fpclassify (__real__ x);
int icls = fpclassify (__imag__ x);
if (__builtin_expect (rcls <= FP_INFINITE || icls <= FP_INFINITE, 0))
{
if (icls == FP_INFINITE)
{
__real__ res = __copysignl (0.0, __real__ x);
__imag__ res = __copysignl (M_PI_2l, __imag__ x);
}
else if (rcls == FP_INFINITE || rcls == FP_ZERO)
{
__real__ res = __copysignl (0.0, __real__ x);
if (icls >= FP_ZERO)
__imag__ res = __copysignl (M_PI_2l, __imag__ x);
else
__imag__ res = __nanl ("");
}
else
{
__real__ res = __nanl ("");
__imag__ res = __nanl ("");
}
}
else if (__builtin_expect (rcls == FP_ZERO && icls == FP_ZERO, 0))
{
res = x;
}
else
{
long double i2 = __imag__ x * __imag__ x;
long double num = 1.0L + __real__ x;
num = i2 + num * num;
long double den = 1.0L - __real__ x;
den = i2 + den * den;
long double f = num / den;
if (f < 0.5L)
__real__ res = 0.25L * __ieee754_logl (f);
else
{
num = 4.0L * __real__ x;
__real__ res = 0.25L * __log1pl (num / den);
}
den = 1 - __real__ x * __real__ x - i2;
__imag__ res = 0.5L * __ieee754_atan2l (2.0L * __imag__ x, den);
}
return res;
}
weak_alias (__catanhl, catanhl)