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HP Forum Archive 11

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HP98x0 machine code info?
Message #1 Posted by Tony Duell (UK) on 24 Mar 2003, 7:54 p.m.

Doe anyone have any information on the machine code of the processor used in the HP9810/HP9820/HP9830 machines? I've read the HP Journal articles here, and I've read the appropriate section of Gordon Bell's book. I also have a good idea as to what the processor hardware does. Wht I am ideally looking for is an opcode table/map of this processor (i.e. what the various 16 bit instructions do). Does anyone have such information?

Re: HP98x0 machine code info?
Message #2 Posted by Rick Bensene on 24 Mar 2003, 11:33 p.m.,
in response to message #1 by Tony Duell (UK)

One of the patents for the 9820 has a complete listing of the microcode for the machine. The architecture of the processor is very similar to the early HP 211x CPU's. From reading through the listings, it's possible to figure out the instruction set. The listings contain both the assembly code, as well as the machine code.

I haven't studied it deeply enough to generate an instruction set listing, but I'm sure that there's enough information there to figured it all out.

The patent number is 3839630. You can get to it at, all you need is a PDF viewer.

Hope that this helps!

Rick Bensene The Old Calculator Web Museum

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