[comp.arch] special purpose architectures

msp33327@uxa.cso.uiuc.edu (Michael S. Pereckas) (02/09/91)

In <26337@dime.cs.umass.edu> yodaiken@chelm.cs.umass.edu (victor yodaiken) writes:

>In article <BBC.91Feb8091541@sicilia.rice.edu> Benjamin Chase <bbc@rice.edu> writes:
>>
>>Providing hardware support specifically for these things is unwise.
>>The expected performance benefit does not justify the required
>>additional complexity of the hardware.  Trigonometric and exponential
>>functions represent a minute fraction of the average instruction usage
>>of general purpose computers.  We all understand that you are not
>>doing general purpose computing.  We don't care.  We are very sorry
>>that your computer usage represents a minority, and thus has less
>>clout when it comes time to design hardware, languages, etc., etc.
>>

>It might be more interesting to have a discussion about the
>diffculty of special purpose architectures and the appropriate
>achitectures for scientific computation than to have a discussion about
>marketing requirements. Programmable architectures, in which users could
>configure the machine for a particular algorithm have implications for
>architectures, programming languages and operating systems. I know that
>there have been some attempts at such architectures (mostly programmable
>pipelines), but would like to
>hear about current efforts and/or reasons why such designs would be good or
>bad ideas. 

Sounds like a systolic array.  Wasn't someone (Intel?) working on some
sort of spiffy programmable systolic array?  I recall hearing
something a while ago.  The idea is appealing, but I'm not certain how
wide a range of problems it would be useful for.  I also wonder
whether compilers could effectivly produce code for a systolic array
from dusty deck source code.  Efficient auto-vectorizing fortran
compilers greatly helped the acceptance of vector supercomputers,
after all.  One imagines that time sharing might be a problem, also,
considering how much state information might have to be saved and
restored.

--


Michael Pereckas               * InterNet: m-pereckas@uiuc.edu *
just another student...          (CI$: 72311,3246)
Jargon Dept.: Decoupled Architecture---sounds like the aftermath of a tornado

sef@kithrup.COM (Sean Eric Fagan) (02/09/91)

In article <1991Feb9.015302.5003@ux1.cso.uiuc.edu> msp33327@uxa.cso.uiuc.edu (Michael S. Pereckas) writes:
>Sounds like a systolic array.  Wasn't someone (Intel?) working on some
>sort of spiffy programmable systolic array?  

"In essence, Splash is a programmable linear logic array that can be
configured to suit the problem at hand; it bridges the gap between the
traditional fixed-function VLSI systolic array and the more versatile
programmable array."

Not quote what you wanted, but close, I suspect.  The quote above is taken
from "Building and Using a Highly Parallel Programmable Logic Array," by
Maya Gokhale et al, Supercomputing Research Center, and Daniel Lopresite,
Brown University.  I found it in the January 1991 issue of "Computer," which
was "Experimental Research in Computer Architecture."  (Actually, a friend
was reading the article, which I'd only skimmed, and he ranted and raved
about it for almost a week 8-).)

-- 
Sean Eric Fagan  | "I made the universe, but please don't blame me for it;
sef@kithrup.COM  |  I had a bellyache at the time."
-----------------+           -- The Turtle (Stephen King, _It_)
Any opinions expressed are my own, and generally unpopular with others.