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Re: 65020 CPU? Look this...



Moll wrote:
Michael J. Mahon wrote:

It would be quite difficult to write RWTS in a real-time OS environment.
Even when interrupt latency is just a few microseconds, by the time
you've executed a few dozen instructions, you could be off my many
microseconds, depending on cache hits and misses.

Of course, one could just stop depending on cycle-accurate instruction
timings--but that wouldn't be an Apple II.


What about cycle accuracy in 8-bit mode only?

That could be done, and was what I was referring to as "lockstep" mode,
where the CPU's internal operations would be synchronized to the bus.

However, this would amount to a _huge_ slowdown, and few designers
would consider this mode interesting enough to put up with its
inevitable encumbrances on an otherwise fast design.

-michael

New Applesoft BASIC interface for NadaNet networking!
Home page:  http://members.aol.com/MJMahon/