My full precision class is my own and is not intended to be general, it can be adjusted for Mandelbrot fractals as much as needed

When I made it I had an idea that if the number of digits in each integer in the array would be fewer, I would win performance since overflow would not having to be checked, ideally not at all. I compared it with IBM's decNumber and by Wikipedia referred ttmath, and mine was twice as fast when it came to multiplying.
I later rewrote it to use fixed decimal positions, and it got another 2 times faster.
So I was pleased with that and I haven't touched it much since my very first fractal video 1.5 years ago (18th October 2012
http://www.youtube.com/v/PvPk&rel=1&fs=1&hd=1 )
I know that some very smart guys have worked many years with a Mandelbrot program, and they also published a number of articles about it. I have read and adopted only one of these articles, the one about squaring, so I have indeed more to learn in this area.
Here is a snippet of the very calculation of the reference:
for(i=0;i<m_nMaxIter && !m_bStop;i++){
m_db_dxr[i] = xr.ToDouble();
m_db_dxi[i] = xi.ToDouble();
m_db_z[i] = (m_db_dxr[i]*m_db_dxr[i] + m_db_dxi[i]*m_db_dxi[i])*0.0000001;
xin = (xr*xi).Double() + m_iref;
xrn = sr - si + m_rref;
xr = xrn;
xi = xin;
sr = xr.Square();
si = xi.Square();
m_nRDone++;
}
One thing to note - I use C++ operators which might not be the most effective, since they create temporary variables out of my control.
I have implemented a Square function, according to the above, and a Double function that instead of multiplying with 2 does a bit-wise shift, but that's about it when it comes to optimizations.
Also note that the threshold values are stored in a 3rd double array, m_db_z, to be used for glitch detection. Those extra 6 double operators also takes some time.
The reference calculation has not been my main concern, but any help on making this faster is much appreciated

Kalle, do you have any statistics about the 32/64 bit download ratio of KF?
I am sorry I have no statistics of downloads of my program.
Maybe Chillheimer has?
It would of course also be interesting for me...
