Subject: Re: PII vs 21164
To: Tom Vier <>
From: Francis. Javier Mesa <>
List: port-alpha
Date: 05/16/2003 17:11:21
> afaik, there is little or no difference between microcode and uops. do
> microcoded cisc cpus use some sort of state machine to execute the
> instructions, vs a modern x86 chip breaking down x86 ops into many fixed
> size uops?

uops are a form of microcode really IMHO, I think the only difference is
that uops are a bit more "risc-y" than traditional microcode. And are geared
towards pipelining, i.e. the actual decoding is fully dynamic to schedule
the uops so that the pipe is as full as possible. I think microcode
(classic microcode anyways) was a strict one to one translation, since
there was no pipelining concerns or anything.