Information Request: unidentified HP 9825T instructions

Tony Duell ard.p850ug1 at
Wed Feb 15 00:26:03 CST 2017

On Wed, Feb 15, 2017 at 1:57 AM, Noel Chiappa <jnc at> wrote:
>     > From: Tony Duell
>     > Having other hardware decode instructions that appear as NOPs to the
>     > main processor is not uncommon in HP machines.
> Ah, so you actually had some prior knowledge that helped in working out that
> puzzle, that that's what's happening here! :-)

Nothing that isn't now available to anyone, like 'my' schematics of
the 9825 memory
boards, the HP41 machine code programming info (think of things like the printer
controller IC), etc.


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