Re: Architecture / Instruction Set / Language co-design.

Charles Richmond <>
Wed, 20 Jul 2011 01:10:17 -0500

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Related articles
Re: Architecture / Instruction Set / Language co-design. (Mark Thorson) (2011-07-18)
Re: Architecture / Instruction Set / Language co-design. (Michael S) (2011-07-19)
Re: Architecture / Instruction Set / Language co-design. (Charles Richmond) (2011-07-20)
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From: Charles Richmond <>
Newsgroups: comp.arch,comp.compilers,alt.folklore.computers
Date: Wed, 20 Jul 2011 01:10:17 -0500
Organization: Canine Computer Center
References: <> 11-07-028
Keywords: design
Posted-Date: 23 Jul 2011 02:39:53 EDT

On 7/18/11 5:26 PM, Mark Thorson wrote:
> It could be argued that the National Semiconductor NS16032 (later
> renamed NS32016) qualifies. The designers Les Kohn and Dan O'Dowd
> started with an instruction set more-or-less based on the VAX and
> pared it down to what they considered a minimum. Dan wrote a Pascal
> compiler that guided the design of the architecture in the sense that
> every time the chip designers in Israel asked whether they could
> delete a feature Les would turn to Dan and ask how that would affect
> the compiler. That chip was intended to be a general-purpose
> architecture, but the compiler guided decisions on what features were
> important.
> Four instructions were deleted relatively late in the design process,
> and you can see the places where they would have been if you look at
> any early 32000 family die. There are four clear stripes that span
> the microcode ROM. I believe these are visible on all 32000 family
> devices through the NS32332. If I remember correctly, the CPU was
> reimplemented in the NS32532, at which point the stripes disappeared.
> [Too bad they didn't have time to debug the chip before they shipped
> it. The NS chips, at least the early ones, were so buggy as to be
> almost unusable. -John]

Yes, I was very interested in the instruction descriptions for the
NS32016. Seems it had a "CASE" assembly language instruction.
But I heard that the chip had hardware problems that were *never*
worked out... Too bad.

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