HP97 The journey begins

[teenix]

Hi all,

We've been put into Covid lockdown again for awhile so I thought I'd use the downtime to keep playing.

So far with the emulator, I've implemented the 67 Continuous Memory and RAM swapping, which increased the storage register count to 104. To make it a bit more flexible, I added the ability to do a simple STO and RCL to/from any register in any bank. Normal STO and RCL still works within a single bank.

Due to the complexity of the 67 Microcode, (which I am loathe to change), other 67 functions like STO+, RCL(i) etc are still standard and can only be used within a single bank.

The 67 Microcode is still running as original, but accessing a bank function requires a stack lift as the info for the access comes from data entered into the X register. However, after the bank access executes, the calculator will be in a state where a new number entry will not lift the stack, as for example, if you just pressed CLx. This way, the access data in the X register will be overwritten. It should be possible to use DZ(i) etc, and the I register to bank swap and do STO or RCL to different banks also, as long as the I register is loaded into X.

I'll try to implement memory banking for the PRGM memory next, then port it all to the newer 67 CPU board.

cheers

Tony