Re: Flame-o-Rama! (was Re: ZipGS 12MHz on ROM

[bazyar@netcom.com (Jawaid Bazyar)]

jimwong@owlnet.rice.edu (Jim Wong) writes:

>What are you talking about?  I was not aware that the 65816 has an instruction
>pipeline of any considerable length.  For what it's worth, though,
>a 40 MHz 68040 would probably eat a 12 MHz 65816 for lunch (not that it
>means anything).

  Leaving out floating point, and ignoring the fact that a 12MHz _GS_
is not the same as a 12MHz 65816, the 12MHz 65816 would keep up pretty
well with such a monster chip as a 040/40. Of course, the 040/40
can move 32 bits in one memory fetch (which is several cycles, usually)
and that is the main disadvantage of 8-bit bus architectures. 

  A IIGS built around a 12MHz 65816 (from scratch, no intermediate
cache) and running the existing system software would fly so fast
you wouldn't know what to do with yourself :-)

  The 65816 does some simple and clever tricks that are pseudo-pipelining,
but which improve the performance of the processor.

  Also, let's not forget that a 20MHz 816 costs $100, and a 40Mhz 040
costs $500. It's not just performance, it's price/performance.

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