Microcode, which is a no-go for modern designs

Paul Birkel pbirkel at gmail.com
Wed Jan 2 02:31:02 CST 2019


>-----Original Message-----
>From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Carlo Pisani via cctalk
>Sent: Tuesday, January 01, 2019 5:35 PM
>To: ben; General Discussion: On-Topic and Off-Topic Posts
>Subject: Re: Motorola M88K books & user manuals (looking for)
>
>> I was never a fan of RISC architecture as does not fit the standard high
>> level language model. Everybody wants a 1 pass compiler, thus the RISC
>> model. If you are doing your own RISC model, you might consider a model
>> that supports Effective addressing better since we have got the point
>> where fetching the data is taking longer than processing it.
>
>yup. I am a 68k programmer so I know what you mean.
>the 68k is more comfortable to be programmed in assembly, and even the
>EA modes (especially in the 68020 and CPU32) help a lot.
>
>unfortunately, the 68K is very complex to be designed, and the first
>68020 used microcode, which is a no-go for modern designs.
>
>...

I'm curious as to why you make this claim that microcode is no-go in "modern" designs.  Could you please elaborate on this point?  I don't see why the alternative random control logic would be a better proposition.

Thanks,
paul



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