Retro68/gcc/libquadmath/math/catanq.c

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2012-03-27 23:13:14 +00:00
/* Return arc tangent of complex __float128 value.
Copyright (C) 1997, 1998 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 "quadmath-imp.h"
__complex128
catanq (__complex128 x)
{
__complex128 res;
int rcls = fpclassifyq (__real__ x);
int icls = fpclassifyq (__imag__ x);
if (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE)
{
if (rcls == QUADFP_INFINITE)
{
__real__ res = copysignq (M_PI_2q, __real__ x);
__imag__ res = copysignq (0.0, __imag__ x);
}
else if (icls == QUADFP_INFINITE)
{
if (rcls >= QUADFP_ZERO)
__real__ res = copysignq (M_PI_2q, __real__ x);
else
__real__ res = nanq ("");
__imag__ res = copysignq (0.0, __imag__ x);
}
else if (icls == QUADFP_ZERO || icls == QUADFP_INFINITE)
{
__real__ res = nanq ("");
__imag__ res = copysignq (0.0, __imag__ x);
}
else
{
__real__ res = nanq ("");
__imag__ res = nanq ("");
}
}
else if (rcls == QUADFP_ZERO && icls == QUADFP_ZERO)
{
res = x;
}
else
{
__float128 r2, num, den;
r2 = __real__ x * __real__ x;
den = 1 - r2 - __imag__ x * __imag__ x;
__real__ res = 0.5 * atan2q (2.0 * __real__ x, den);
num = __imag__ x + 1.0;
num = r2 + num * num;
den = __imag__ x - 1.0;
den = r2 + den * den;
__imag__ res = 0.25 * logq (num / den);
}
return res;
}