Information Request: unidentified HP 9825T instructions

Eric Smith spacewar at
Tue Feb 14 00:24:37 CST 2017

On Mon, Feb 13, 2017 at 12:35 PM, Tony Duell <ard.p850ug1 at> wrote:

> That seems possible, yes.
> Having other hardware decode instructions that appear as NOPs to the main
> processor is not uncommon in HP machines.

And it's even common in HP machines for such instructions to be used for
ROM bank switching.

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