🚀 go-pugleaf

In article <5990@pt.cs.cmu.edu> lindsay@MATHOM.GANDALF.CS.CMU.EDU (Donald Lindsay) writes:
>
>If the hardware has been designed to do "instruction continuation",
>then the user program will resume somewhere in the middle of the
>offending instruction. If the hardware has been designed for
>"instruction restart", then the program will be resumed at the start
>of the offending instruction. The user-visible result is the same in
>both cases. 
>
I guess this is where I'm having a problem.  What if the instruction
involved address increment/decrement modes?  Restarting the instruction
might not give the exact same result unless the results of auto-inc/dec
were not placed into the affected registers until the instruction completes.

I remember reading some literature when the 68010 came out explaining the
wonderful benefits of instruction continuation and why instruction restart
did not always solve the problem.  (I don't remember *where* I read this.)
Now I'm hearing that it doesn't really matter.  Instruction restart makes
a lot more sense to me as long as the side effects of the instruction are
not not interruptable.  Is this the case with the 68040?

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Scott Amspoker
Basis International, Albuquerque, NM
505-345-5232