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/* Pythagorean addition using doubles
Copyright (C) 2011-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library
Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <math-underflow.h>
#include <stdint.h>
#include <libm-alias-finite.h>
/* __ieee754_hypot(x,y)
*
* This a FP only version without any FP->INT conversion.
* It is similar to default C version, making appropriates
* overflow and underflows checks as well scaling when it
* is needed.
*/
double
__ieee754_hypot (double x, double y)
{
if ((isinf (x) || isinf (y))
&& !issignaling (x) && !issignaling (y))
return INFINITY;
if (isnan (x) || isnan (y))
return x + y;
x = fabs (x);
y = fabs (y);
if (y > x)
{
double t = x;
x = y;
y = t;
}
if (y == 0.0)
return x;
/* if y is higher enough, y * 2^60 might overflow. The tests if
y >= 1.7976931348623157e+308/2^60 (two60factor) and uses the
appropriate check to avoid the overflow exception generation. */
if (y <= 0x1.fffffffffffffp+963 && x > (y * 0x1p+60))
return x + y;
if (x > 0x1p+500)
{
x *= 0x1p-600;
y *= 0x1p-600;
return sqrt (x * x + y * y) / 0x1p-600;
}
if (y < 0x1p-500)
{
if (y <= 0x0.fffffffffffffp-1022)
{
x *= 0x1p+1022;
y *= 0x1p+1022;
double ret = sqrt (x * x + y * y) / 0x1p+1022;
math_check_force_underflow_nonneg (ret);
return ret;
}
else
{
x *= 0x1p+600;
y *= 0x1p+600;
return sqrt (x * x + y * y) / 0x1p+600;
}
}
return sqrt (x * x + y * y);
}
#ifndef __ieee754_hypot
libm_alias_finite (__ieee754_hypot, __hypot)
#endif
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