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From: kevin@tolerant.UUCP
Newsgroups: net.micro.ns32k
Subject: Re: Re: Re: National's 32332 (Apples and oranges really)
Message-ID: <367@tolerant.UUCP>
Date: Sat, 14-Jun-86 02:47:45 EDT
Article-I.D.: tolerant.367
Posted: Sat Jun 14 02:47:45 1986
Date-Received: Sat, 14-Jun-86 20:11:26 EDT
References: <746@usl.UUCP> <253@spar.UUCP> <2793@sdcrdcf.UUCP>
Distribution: na
Organization: Tolerant Systems, Inc.  San Jose, CA
Lines: 75

> > > 	In order for the 15 MHz 32332 to be faster than an 68020 (much less
> > > a 386) it would have be 3x faster than an 10MHz 32032.  The increased
> > > clock frequency accounts for 1.5x, I am hard pressed to imagine where
> > > the other 2x could come from.
> > 
> > I may find that hard to imagine.  But why would you?
> > If we are to believe the Dhrystone figures posted to the net,
> > your company did just that in going from the 8086 to the 80286, ie.
> > obtained a 2x speedup for the same clock frequencies.
> > 
> My point was not that PC-ATs and 286 are faster than 32032.  This 
> point (really 16-bits vs 32-bits) has being debated for some time on the 
> network and I doubt that there is anything more either one of us
> could add to the discussion. 
> 
> Rather my point was what significant architectural improvements were made
> to the 32332 to give it a 2x performance boost at the same clock frequency?
> 
> After reading the data sheet and other information on the part I am only
> aware of a few improvements made to the 32332 vs 32032.
> 	1. Burst Mode Bus, useful for cache systems and possibly
> 	   DMA-like transfers
> 	2. 32 address lines, no performance increase
> 	3. large prefetch unit, some performance boost.
> 
> How could these architectural improvements double the performance?
> It is certainly possible that I may have overlooked some important things
> since I can no longer find my 32332 literature.  However in my opinion
> the main improvement that the 32332 has over the 32032 is clock speed.
> The clock speed boost alone would not make it faster than a 68020. 
> 
> In contrast, there were many architectural improvements in the 86 vs the 286.
> Additional commonly used instructions e.g. push immediate, faster multiply etc.
> The most important 8086 to 286 improvement was the addition of special
> purpose hardware to calculate the effective address.  Effective address
> calculation which took 6-12 clocks on an 8086 take only 1 clock on the
> 286.  This resulted in an almost 2/3 reduction in average clocks/instruction
> between an 8086 and 286.  This is responsible for the 2.5-3x performance
> advantage at the same clock frequency.

National also added special a special purpouse ALU to the 32332 to calculate
the effective address. And I beleive that this accounts for significant amount
of the additional speed fo the 32332.

> 
> The major architecture improvement of the 386 compared to the 286 is going from
> 16-bits to 32-bits.  The other improvements, orthogonal registers, the
> addition of scaled-index addressing, and the shaving of 1 clock of the
> execution of most common instructions, while important, are not as
> dramatic as the 8086 to 80286 performance improvements.  
> 

National a reduced the number of clock cycles per bus cycle. I believe the
that bus cycles are now 2 clock cycles without an MMU and 3 with an MMU.
Where as the 32032 is 4 clock cycles per bus cycle with out an MMU and 5
clock cycles with an MMU. It's been quite some time since I saw National's
presentation so I may not be entrierly correct about the numbers, but I
do remember that there are less clock cycles per bus cycle.

> I standby my statement that I do not believe that an 15MHz 32332 is faster
> than a 16.7 MHz 68020 (much less a 80386).  If somebody actually gets
> 4000+ Dhrystones from a 32332 I would be surpised.   While I do not 
> believe that Dhrystones are a perfect measurement of performance, I
> think they are pretty darn good.  
> -- 

The National 32032, 32332, and the Motorola 680XX both have a much better 
instuction set than the Intel 8086, 186, 286, and 386. This may not be
as noticible at the machine code level, but when in compiled codes, especialy
'C', the National and Motorola instrucitons sets are much more efficient.


-- 
Kevin Flory @ Tolerant Systems, San Jose CA
..{bene,mordor,nsc,oliveb,pyramid,ucbvax}!tolerant!kevin