PDP-8/L not incrementing properly

From: Sebastian Brückner <sebastian.brueckner_at_epost.de>
Date: Sun Nov 9 15:23:59 2003

Hi!

I once again tried to get my PDP-8/L to run this weekend. Unfortunately
I am not not yet a PDP professional - I don't have a clue what most of
the modules are doing. I started to read the Maintenance Manuals but I
do not quite know where to start. Maybe you can give me a hint:

I tried the "simpler" instructions like set accumulator, or accumulator
with switch reg. etc.
What I did not yet try are the different jump instructions. I will be
more specific as soon as I tried more instructions.

CLA and STA work, i can set all bits in AC. IAC (increment) and all the
rotate instructions however always set AC to 1 completely ignoring the
previous value.
Where should I start looking for the problem? What information do I have
to gather to narrow down the source of the problem?

Regards,
   Sebastian
Received on Sun Nov 09 2003 - 15:23:59 GMT

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