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/* Emulation for sqrtl.
Contributed by Paolo Bonzini
Copyright 2002, 2003 Free Software Foundation, Inc.
This file is part of gnulib.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <float.h>
#include <math.h>
#include "mathl.h"
/* A simple Newton-Raphson method. */
long double
sqrtl(long double x)
{
long double delta, y;
int exponent;
/* Check for negative numbers */
if (x < 0.0L)
return (long double) sqrt(-1);
/* Check for zero, NANs and infinites */
if (x + x == x || x != x)
return x;
frexpl (x, &exponent);
y = ldexpl (x, -exponent / 2);
do
{
delta = y;
y = (y + x / y) * 0.5L;
delta -= y;
}
while (delta != 0.0L);
return y;
}
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