Information Request: unidentified HP 9825T instructions

Pete Lancashire pete at
Mon Feb 13 18:43:59 CST 2017

I agree quite a unique bit of code

On Feb 13, 2017 4:07 PM, "Noel Chiappa" <jnc at> wrote:

    > From: Tony Duell

    > My first thought, and it's probably wrong

Apparently not... :-)

    > these instrucitons (which differ by one bit, so might be
    > setting/reseting something) are NOPs to the CPU, but are interpretted
    > by the memory mapping hardware

Ooh, very clever/cool.


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