mirror of git://gcc.gnu.org/git/gcc.git
96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/* Return arc hyperbole cosine for __float128 value.
|
|
Copyright (C) 1997, 1998, 2006 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
|
|
cacoshq (__complex128 x)
|
|
{
|
|
__complex128 res;
|
|
int rcls = fpclassifyq (__real__ x);
|
|
int icls = fpclassifyq (__imag__ x);
|
|
|
|
if (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE)
|
|
{
|
|
if (icls == QUADFP_INFINITE)
|
|
{
|
|
__real__ res = HUGE_VALQ;
|
|
|
|
if (rcls == QUADFP_NAN)
|
|
__imag__ res = nanq ("");
|
|
else
|
|
__imag__ res = copysignq ((rcls == QUADFP_INFINITE
|
|
? (__real__ x < 0.0
|
|
? M_PIq - M_PI_4q : M_PI_4q)
|
|
: M_PI_2q), __imag__ x);
|
|
}
|
|
else if (rcls == QUADFP_INFINITE)
|
|
{
|
|
__real__ res = HUGE_VALQ;
|
|
|
|
if (icls >= QUADFP_ZERO)
|
|
__imag__ res = copysignq (signbitq (__real__ x) ? M_PIq : 0.0,
|
|
__imag__ x);
|
|
else
|
|
__imag__ res = nanq ("");
|
|
}
|
|
else
|
|
{
|
|
__real__ res = nanq ("");
|
|
__imag__ res = nanq ("");
|
|
}
|
|
}
|
|
else if (rcls == QUADFP_ZERO && icls == QUADFP_ZERO)
|
|
{
|
|
__real__ res = 0.0;
|
|
__imag__ res = copysignq (M_PI_2q, __imag__ x);
|
|
}
|
|
/* The factor 16 is just a guess. */
|
|
else if (16.0Q * fabsq (__imag__ x) < fabsq (__real__ x))
|
|
{
|
|
/* Kahan's formula which avoid cancellation through subtraction in
|
|
some cases. */
|
|
res = 2.0Q * clogq (csqrtq ((x + 1.0Q) / 2.0Q)
|
|
+ csqrtq ((x - 1.0Q) / 2.0Q));
|
|
if (signbitq (__real__ res))
|
|
__real__ res = 0.0Q;
|
|
}
|
|
else
|
|
{
|
|
__complex128 y;
|
|
|
|
__real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
|
|
__imag__ y = 2.0 * __real__ x * __imag__ x;
|
|
|
|
y = csqrtq (y);
|
|
|
|
if (signbitq (x))
|
|
y = -y;
|
|
|
|
__real__ y += __real__ x;
|
|
__imag__ y += __imag__ x;
|
|
|
|
res = clogq (y);
|
|
}
|
|
|
|
return res;
|
|
}
|