Newsgroups: comp.arch
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Unaligned Accesses (was Re: How to use silicon)
Message-ID: <1989Mar25.013342.22214@utzoo.uucp>
Organization: U of Toronto Zoology
References: <37196@bbn.COM> <1989Mar16.190043.23227@utzoo.uucp> <24889@amdcad.AMD.COM> <355@bnr-fos.UUCP> <13@microsoft.UUCP> <362@bnr-fos.UUCP>
Date: Sat, 25 Mar 89 01:33:42 GMT

In article <362@bnr-fos.UUCP> mlord@bnr-public.UUCP (Mark Lord) writes:
>The debate for devoting more silicon space to support efficient handling
>of misaligned accesses seems to hinge around supporting the huge amounts
>of perfectly good software that already exist, written before programmers
>in general became keenly aware of alignment/efficiency tradeoffs.

How quickly we forget.  The lack of attention to alignment/efficiency
tradeoffs was a temporary aberration in the late 70s and early 80s.
I assure you that those of us who wrote code for such unimportant,
commercially-insignificant machines as the 360, the PDP11, and the
68000/010 were keenly aware of such tradeoffs from the beginning, because
the hardware gave us no choice.  I continue to think that the quantity
of good software which disregards alignment is grossly overestimated.
(It is not zero, and attention to it is necessary, but the idea that
a random software package has a 90% chance of suffering from such
carelessness is unjustified.)
-- 
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