mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-01 11:52:47 +00:00
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/* Complex square root of float value.
|
|
Copyright (C) 1997, 1998 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.
|
|
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 <complex.h>
|
|
#include <math.h>
|
|
|
|
#include "math_private.h"
|
|
|
|
|
|
__complex__ float
|
|
__csqrtf (__complex__ float x)
|
|
{
|
|
__complex__ float res;
|
|
int rcls = fpclassify (__real__ x);
|
|
int icls = fpclassify (__imag__ x);
|
|
|
|
if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
|
|
{
|
|
if (icls == FP_INFINITE)
|
|
{
|
|
__real__ res = HUGE_VALF;
|
|
__imag__ res = __imag__ x;
|
|
}
|
|
else if (rcls == FP_INFINITE)
|
|
{
|
|
if (__real__ x < 0.0)
|
|
{
|
|
__real__ res = icls == FP_NAN ? __nanf ("") : 0;
|
|
__imag__ res = __copysignf (HUGE_VALF, __imag__ x);
|
|
}
|
|
else
|
|
{
|
|
__real__ res = __real__ x;
|
|
__imag__ res = (icls == FP_NAN
|
|
? __nanf ("") : __copysignf (0.0, __imag__ x));
|
|
}
|
|
}
|
|
else
|
|
{
|
|
__real__ res = __nanf ("");
|
|
__imag__ res = __nanf ("");
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (icls == FP_ZERO)
|
|
{
|
|
if (__real__ x < 0.0)
|
|
{
|
|
__real__ res = 0.0;
|
|
__imag__ res = __copysignf (__ieee754_sqrtf (-__real__ x),
|
|
__imag__ x);
|
|
}
|
|
else
|
|
{
|
|
__real__ res = fabsf (__ieee754_sqrtf (__real__ x));
|
|
__imag__ res = __copysignf (0.0, __imag__ x);
|
|
}
|
|
}
|
|
else if (rcls == FP_ZERO)
|
|
{
|
|
float r = __ieee754_sqrtf (0.5 * fabsf (__imag__ x));
|
|
|
|
__real__ res = __copysignf (r, __imag__ x);
|
|
__imag__ res = r;
|
|
}
|
|
else
|
|
{
|
|
float d, r, s;
|
|
|
|
d = __ieee754_hypotf (__real__ x, __imag__ x);
|
|
/* Use the identity 2 Re res Im res = Im x
|
|
to avoid cancellation error in d +/- Re x. */
|
|
if (__real__ x > 0)
|
|
{
|
|
r = __ieee754_sqrtf (0.5f * d + 0.5f * __real__ x);
|
|
s = (0.5f * __imag__ x) / r;
|
|
}
|
|
else
|
|
{
|
|
s = __ieee754_sqrtf (0.5f * d - 0.5f * __real__ x);
|
|
r = fabsf ((0.5f * __imag__ x) / s);
|
|
}
|
|
|
|
__real__ res = r;
|
|
__imag__ res = __copysignf (s, __imag__ x);
|
|
}
|
|
}
|
|
|
|
return res;
|
|
}
|
|
weak_alias (__csqrtf, csqrtf)
|