>Did I notice correctly in your profile that you had some assembly experience in the 6502? If I remember correctly, that had the same instruction set as the 6510. I was cleaning out some storage space the other day and came across one of my old reference books on assembly with the 6510. Those were the days, eh.

Oh yes, those were the days. I got my start with the old Atari computers. One of the nicest things about them was that there was a lot of documentation on the OS. There was a memory map to the ROM I/O routines, complete source code listing to the BASIC interpreter, and the same for the DOS. I think I learned more about the underlying workings of computers through the study of that machine. I also received a lot of help (via snail mail) from a fellow by the name of Bill Wilkinson, who use to write a column for Compute! magazine. Bill was a member of the team (with Optimized Systems Software) that wrote both the BASIC and DOS. Very nice guy. They also wrote the original DOS for the Apple ][.

Ah memories. Well, let's get back in VFP mode.

LDA VFPMODE
PHA
LDA VFPMODE + 1
PHA
RTS

< rbg .