Re: 9825 disassembly status

Paul Berger


You understand that there are two 1K word windows into the ROM and the bank selection is done by write to the area occupied by the base page ROM, I think my writeup included with the package gives a good description of how it works.


On 2017-02-11 4:46 PM, Craig Ruff wrote:
I’ve been working on preliminary disassembly of the 9825T ROMs this week, and have some initial symbol information and comments generated for the built in extension ROMs. Nothing to the detail of those from the patent listing, but enough to start deciphering what is going on in each ROM.

I started looking at the banked 98228A disk ROM today. My disassembler currently does not understand banking, so I just have to dump the base page and each of the other banks separately. I did have to byte swap the 16-bit ROM image that Paul provided so that the byte order conformed to those of the mainframe ROMs. I expect that this is done by the ROM pin connections in his clone module. My ROM header decoder script was then happy with the 98228A base page, so I will proceed with some investigation of this ROM’s contents.

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