I was reading your TO-DO list and noticed this entry: Fix uint64 to double conversion You can do this on MSVC6 but only if you have the preprocessor pack installed, I'm not sure why it's required, but if you have it installed it's very easy. A lot of people do have this installed as it's what gives you access SSE and SSE2 instructions (aslong as 3DNow I think). As for why you need this installed to do it, I'm not sure, but it is a Microsoft product :). You can download and read more about it here. Thanks, Jeremy