6502/Z80 speed comparison (was MITS 2SIO serial chip?)

From: Hans Franke <Hans.Franke_at_mch20.sbs.de>
Date: Fri Dec 21 12:37:57 2001

> I'm not at all sure one could fairly say the 6502 was a "stripped down M6800.
> It has 56 documented instructions, not to mention the undocumented ones, so it's
> probably not a RISC. The CMOS version has many more instructions, and it has
> more addressing modes than the MOT processor.

> It does store low-byte-first, though, so, in that respect, it's different from
> the MOT parts.

That, and the missed chance to use the BRK instruktion as an SVC
instruction (*) are the only parts I never liked about the '02.


(*) Yes, I know, the PC was already advanced, and using 12 or so
operations to access the byte to read the byte which has already
been on the date bus is possible, and often done, none the less,
it's a huge missed chance.

VCF Europa 3.0 am 27./28. April 2002 in Muenchen
Received on Fri Dec 21 2001 - 12:37:57 GMT

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