Go To in Woodstocks

[teenix]

Hi all,

My first post :-)

I used to own a HP-45 back in the 70's onwards and I saw one some months back and it inspired me to have ago at creating my own. After delving into it, I had no idea there were so many people interested in such things, but I can understand why.

Anyway I get some free time working in remote areas and after many headaches and relying on other talented peoples past efforts I finally got it working. Afterwards I got the "HP bug" well and truly and decided to carry on with other models and now have the 6 Classic Series models working as a Windows application. It also has a compiler and debugger.

I also have all of them working as a real operating calculator complete with bubble LEDs and hardware memory cards for the HP-65.

I am doing this only as a personal challenge to stop my diminishing old grey matter from turning into don't matter and I would like to try the 67 next.

I have found code segments that appear to jump across ROM boundaries and as the instructions are only 10 bits with 8 for the target address I cannot see how this is accomplished. If this is indeed the case then having delayed select ROM n instructions would seem unnecessary.

I am obviously missing something but with limited resources I have ground to a halt.

Any insights for this problem are surely appreciated.

many thanks

cheers

Tony