/* Emulation for sqrtl.
Contributed by Paolo Bonzini
Copyright 2002, 2003, 2007, 2009, 2010 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 3 of the License, 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, see . */
#include
/* Specification. */
#include
#include
/* A simple Newton-Raphson method. */
long double
sqrtl (long double x)
{
long double delta, y;
int exponent;
/* Check for NaN */
if (isnanl (x))
return x;
/* Check for negative numbers */
if (x < 0.0L)
return (long double) sqrt (-1);
/* Check for zero and infinites */
if (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;
}