mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-21 04:31:04 +08:00
76 lines
2.3 KiB
C
76 lines
2.3 KiB
C
/* Copyright (C) 2005-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <stdbool.h>
|
|
#include <math.h>
|
|
#include <complex.h>
|
|
|
|
attribute_hidden
|
|
long double _Complex
|
|
__divtc3 (long double a, long double b, long double c, long double d)
|
|
{
|
|
long double denom, ratio, x, y;
|
|
|
|
/* ??? We can get better behavior from logarithmic scaling instead of
|
|
the division. But that would mean starting to link libgcc against
|
|
libm. We could implement something akin to ldexp/frexp as gcc builtins
|
|
fairly easily... */
|
|
if (fabsl (c) < fabsl (d))
|
|
{
|
|
ratio = c / d;
|
|
denom = (c * ratio) + d;
|
|
x = ((a * ratio) + b) / denom;
|
|
y = ((b * ratio) - a) / denom;
|
|
}
|
|
else
|
|
{
|
|
ratio = d / c;
|
|
denom = (d * ratio) + c;
|
|
x = ((b * ratio) + a) / denom;
|
|
y = (b - (a * ratio)) / denom;
|
|
}
|
|
|
|
/* Recover infinities and zeros that computed as NaN+iNaN; the only cases
|
|
are nonzero/zero, infinite/finite, and finite/infinite. */
|
|
if (isnan (x) && isnan (y))
|
|
{
|
|
if (denom == 0.0 && (!isnan (a) || !isnan (b)))
|
|
{
|
|
x = copysignl (INFINITY, c) * a;
|
|
y = copysignl (INFINITY, c) * b;
|
|
}
|
|
else if ((isinf (a) || isinf (b))
|
|
&& isfinite (c) && isfinite (d))
|
|
{
|
|
a = copysignl (isinf (a) ? 1 : 0, a);
|
|
b = copysignl (isinf (b) ? 1 : 0, b);
|
|
x = INFINITY * (a * c + b * d);
|
|
y = INFINITY * (b * c - a * d);
|
|
}
|
|
else if ((isinf (c) || isinf (d))
|
|
&& isfinite (a) && isfinite (b))
|
|
{
|
|
c = copysignl (isinf (c) ? 1 : 0, c);
|
|
d = copysignl (isinf (d) ? 1 : 0, d);
|
|
x = 0.0 * (a * c + b * d);
|
|
y = 0.0 * (b * c - a * d);
|
|
}
|
|
}
|
|
|
|
return x + I * y;
|
|
}
|