gnu/lib/libg++/libg++/sqrt.cc

/*
Copyright (C) 1990 Free Software Foundation
    written by Doug Lea (dl@rocky.oswego.edu)

This file is part of the GNU C++ Library.  This 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.  This 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 this library; if not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifdef __GNUG__
#pragma implementation
#endif
#include <builtin.h>
#include <math.h>

long sqrt(long x)
{
  if (x <= 0)
    return 0;                   // no int error handler, so ...
  else if (x == 1)
    return 1;
  else
  {
    long r = x >> 1;
    long q;
    for(;;)
    {
      q = x / r;
      if (q >= r)
        return r;
      else
        r = (r + q) >> 1;
    }
  }
}