KDJ11 misfeature

Noel Chiappa jnc at mercury.lcs.mit.edu
Sun Jul 8 18:45:54 CDT 2018


So, it appears that the KDJ11 (definitely the -A, and probably all of them)
cannot execute code from the PARs - one gets a NXM trap. (Definitely the
kernel I PARs, I haven't checked all 6 sets, but I can't see why they others
would be any different.) Has anyone else run into this, so I can be sure I'm
not confused?

This is a mild pain, because it's nice to be able to put short 'scope loops in
them, either to debug a memory card when you don't have any working memory
plugged in, or when you don't want the bus 'contaminated' with instruction
fetch cycles, etc.

      Noel


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