[GTALUG] example of why RISC was a good idea

James Knott james.knott at rogers.com
Sat May 21 14:48:50 EDT 2016


On 05/21/2016 01:33 PM, D. Hugh Redelmeier wrote:
> A RISC processor would not have a complex instruction decoder so this kind 
> of hacking would not apply.  I will admit that there are "hazards" in RISC 
> processors that are worth paying attention to when selecting and ordering 
> instructions but these tend to be clearer.

Many years ago, I used to maintain Data General Eclipse systems.  The
CPU used microcode to control AMD bit slice processors and associated
logic.  The microcode instructions were over 100 bits wide.  Now
*THAT'S* RISC.  ;-)

BTW, those CPUs had an option called Writable Control Store (WCS) where
one could create custom instructions.



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