Re: Multiprocessor 65816???

[mjmahon@aol.com (Michael J. Mahon)]

Peter Watson wrote:

>"Eric Smith" <eric-no-spam-for-me@brouhaha.com> wrote in message
>qhoetuaidz.fsf@ruckus.brouhaha.com">news:qhoetuaidz.fsf@ruckus.brouhaha.com...
>> "Bryan Parkoff" <bryan.nospam.parkoff@nospam.com> writes:
>> >     I am surprised that there is no virtual memory existence for Apple
>IIgs
>> > since Abort feature is available.  Do you think that GS/OS can implment
>to
>> > use Abort feature so visual memory can be enabled?
>>
>> Proper virtual memory would require an MMU in addition to the abort
>> feature.
>>
>> >     I wonder why COP instruction is never used.  It may be useful for
>> > floating.
>>
>> Not particularly useful, since no coprocessor was ever sold.
>
>How did the FPE (Floating Point Engine) card work?

Like all other "coprocessors" for the Apple II, it was just "another"
processor, in the sense that it was invoked as a peripheral through
I/O addresses.

A true coprocessor runs from the same instruction stream as
the main processor, with the main processor logic "handing off"
execution of certain instructions to the coprocessor.

-michael

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