🚀 go-pugleaf

In article <DE6soL.or@world.std.com> jimf@world.std.com (jim frost) writes:
>dpg1@cam-orl.co.uk (Duncan Grisby) writes:
>>Presumably there will be a major problem with porting the
>>memory protection onto any 680x0 without an MMU -- that's
>>all 68000s and 68020s, and quite a lot of 030s and 040s.
>
>I'm not sure exactly what you're trying to say here but *all* 030's
>and 040's have a built-in MMU.

Wrong.  Not *all* 030s and 040s have an MMU.  There are EC versions
of these chips which are pin-for-pin replacements.  The EC030 does
not have an MMU, and the EC040 is missing the FPU and (I believe)
the MMU.

The 68020 could use an external MMU (68551?) and I am not sure what,
if anything, could be done with a 68000/68010.

The differences between an RC020 (full) and the 68EC020 used in the
A1200 are primarily external.  i.e. there are only 24-address lines
instead of 32.  I don't recall if the data bus is different.

>jim frost
>jimf@world.std.com
>-- 
>http://world.std.com/~jimf

Let's get our facts straight!  If you are not sure about something,
you can state it in such a way as to make that clear.  Remember...
some people actually BELIEVE things people write.
-- 

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Jeffrey W. Davis (317)451-0503   Domain: c23jwd@kocrsv01.delcoelect.com
Software Engineer                UUCP:   deaes!c23jwd