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From: jans@tekecs.UUCP (Jan Steinman)
Newsgroups: net.micro.ns32k
Subject: Re: National's 32332 (Apples and oranges really)
Message-ID: <7332@tekecs.UUCP>
Date: Wed, 11-Jun-86 12:38:20 EDT
Article-I.D.: tekecs.7332
Posted: Wed Jun 11 12:38:20 1986
Date-Received: Thu, 12-Jun-86 01:44:35 EDT
References: <746@usl.UUCP> <253@spar.UUCP> <2793@sdcrdcf.UUCP>
Reply-To: jans@tekecs.UUCP (Jan Steinman)
Distribution: na
Organization: Tektronix, Wilsonville OR
Lines: 34

>> 	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.

Those who can't imagine where Nati could find the time have not carefully
examined the instruction times.  Two areas stand out like a sore thumb:
memory access time (5 clocks per int on the 32032 with MMU, even more for
32016), and address calculation time.  Since this was Nati's first major
CPU in quite a while, I see no reason to doubt that memory access times
could be improved to the 'state of the are' times found in Intel or Mota
products.

The address times are particularly depressing on the 32032.  As a
specialist in fast interpreters, I'm not particularly pleased with how
Nati apparently dealt with this, but deep prefetch is the classical way
of improving address calculation *throughput*, if not time, and the
addition of the barrell shifter would certainly improve the scaled index
calculation times.

In all, I find it just as plausible that Nati can improve their first cut
by a factor of three as it is that Mota can do the same.  I find it harder
to imagine that Intel can improve their `nth' cut by a similar margin!
How about it, guys?  Why so much silicon to get to the same place Nati got
in two tries?
-- 
:::::: Artificial   Intelligence   Machines   ---   Smalltalk   Project ::::::
:::::: Jan Steinman		Box 1000, MS 60-405	(w)503/685-2956 ::::::
:::::: tektronix!tekecs!jans	Wilsonville, OR 97070	(h)503/657-7703 ::::::