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Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!houxm!vax135!cornell!uw-beaver!tikal!sysad
From: sysad@tikal.UUCP (sysad)
Newsgroups: net.arch
Subject: Re: Arbitrary byte alignment
Message-ID: <36@tikal.UUCP>
Date: Fri, 19-Oct-84 21:54:12 EDT
Article-I.D.: tikal.36
Posted: Fri Oct 19 21:54:12 1984
Date-Received: Sun, 21-Oct-84 14:48:05 EDT
References: <122@anwar.UUCP>
Organization: Teltone Corp., Kirkland, WA
Lines: 28



>>A note about the Pyramid 90x.  After further discussion between
>>software and hardware engineers, it was determined that it wouldn't be
>>very difficult or expensive (speedwise) to implement almost arbitrary
>>byte alignment (e.g. longwords accessed on any even address) in the
>>microcode.  Pyramid will be offering this microcode change to its'
>>customers real soon now.
>>
>>I think this implies that arbitrary byte alignment does not necessarily
>>imply a performance penalty in the global throughput of a machine.
>>
>>I know compilers can be taught to do alignment, but many programmers
>>using C's simple address arithmetic mechanisms, can't be. :-)

I can tell you from recent bitter experience that Pyramid will NOT be
offering this microcode change to ANYONE, anytime.  It seems that when
HHB Softron decided to re-port its code, Pyramid decided byte-alignment
was too hard.  Apparently they also decided not to tell anyone.

	Pyramid "software and hardware engineers" also seem to believe
that compilers cannot easily be taught to do alignment.  If you are
expecting arbitrary byte alignment out of Pyramid, you'd better ask
them again.

Duane Hesser
...uw-beaver!tikal!sysad