HP97 The journey begins
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12-08-2021, 01:34 AM
(This post was last modified: 12-08-2021 01:36 AM by teenix.)
Post: #542
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RE: HP97 The journey begins
(12-07-2021 10:14 PM)Massimo Gnerucci Wrote: The 95C microcode would be much more interesting, so we could emulate it on another Topcat. I don't think the 95C microcode is available. The 97 has some spare continuous memory available, so I was toying with the idea of using it to give the 97 similar programming capacity of the 95C which would give it 4 times the program and RAM memory. I was thinking of a simple concept (yeah right - ha ha) whereby the user could switch between 4 memory banks using keys presses like I have for notes printing, ie [f][f][C] would switch program banks depending on what was in register C at the time. Example - If reg C = 2, press [f][f][C], PGM bank 2 becomes active. From the 97's point of view, it is just normal memory and it will execute everything as normal. [f][f][C] is stored as a single program step. You could also have [f][f][D] and C register index to select RAM storage banks. From a coding point of view, the bank swapping is just changing a memory pointer to a base address, however swapping banks in this way means jumping to the current program counter + 1 which would be problematic, as for early Classic microcode jumps. Things like GTO GSB can be limited to current bank, or if global becomes more complex. I think the 95C allowed access between the 4 programs. Card storage would be up to 8 cards for program and data, but I would think to save the poor old card reader that these types of programs would be stored/recalled with internal memory and auto load the entire program or data file. As mentioned, sounds simple but..... Just thoughts :-) cheers Tony |
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