Got the HP-11C firware working well enough in NSIM that it displays “Pr Error” at startup, which is what it’s supposed to do. Then pressing the ON key will get a “0.0000″ display. Nothing beyond that though. At least it’s progress.

I still need to merge the Nut simulator from NSIM into CASMSIM, but for the moment it’s easier to try to debug the 11C running in NSIM.

I dumped the ROM from an HP-32E. I was surprised to find that the Spice series self-test works differently than the Voyager series. There’s a single instruction, 0×330, which apparently computes a checksum of an entire 1K word block of ROM. The Nut CPU used in the Voyager series and HP-41C has an instruction to read a single word of ROM, and that instruction must be used in a loop. Reverse-engineering the Spice series instruction set will be a challenge, though at least it’s similar to the other generations.

On Sunday a friend and I will dump the rest of the Voyager and Spice series ROMs.