HP97 The journey begins

[teenix]

It looks like your listing has 1 extra 10^X, and you omitted 0 - 9 and (.)

So overall, that adds up to 266 programmable steps.

I can whittle it down to 252 codes if I use the following...

LBL 0 - 7 instead of 0 - 9.
GTO 0 -7
GSB0 - 7
JMP ABCD 0 - 7

No extra "goodies" in this project, I think the goodie is the project ;-)

If as you suggest, I use shadow RAM for the 9th bit of the 200 steps, then I need another 30 RAM registers, which is a bit wasteful for the era, but probably doable as there are 3 extra 14 pin ICs on the board compared to the 97. I'm not sure what these are, but they could be extra RAM - 10 registers each was common, 10 x 3 = 30, Hmm - seems to fit.

Off the top of my head, for something simple in code, I could set the Status[15] bit as a flag to determine if a step is 8 or 9 bits. That bit is not used so far in this application. That would determine what to store in the shadow RAM. On recall, s15 is set if the shadow RAM is non-zero.

I'll stick to PICs. I'm too old to go with new development platforms :-)

cheers

Tony