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From: jbuck@galileo.berkeley.edu (Joe Buck)
Newsgroups: comp.arch
Subject: Re: Is handling off-alignment impor
Message-ID: <38216@ucbvax.BERKELEY.EDU>
Date: 17 Aug 90 17:46:00 GMT
References: <12459@encore.Encore.COM> <3300161@m.cs.uiuc.edu> <1990Aug17.155925.1588@mozart.amd.com>
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Reply-To: jbuck@galileo.berkeley.edu (Joe Buck)
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In article <1990Aug17.155925.1588@mozart.amd.com>, davec@nucleus.amd.com
(Dave Christie) writes:
> In article <3300161@m.cs.uiuc.edu> marick@m.cs.uiuc.edu writes:
> >Taking advantage of architectural quirks isn't automatically evil.
> >You just have to weigh the costs against the benefits.

> Unless you know what the architects might come up with in the future
> in the way of architectural extensions, you can't know all the possible
> costs.

If your software design makes use of information hiding, then all code
that depends on the architectural feature will be localized to a very
small portion of code, so converting to a new architecture will be easy.
If you don't use this kind of discipline, yes, porting your software to
a new architecture, or even the next generation of the same architecture,
will be extremely difficult, because cruft that depends, say, on the
meanings of particular bits will appear all over the place.

Yet another reason I'm growing to like C++ more and more...
--
Joe Buck
jbuck@galileo.berkeley.edu	 {uunet,ucbvax}!galileo.berkeley.edu!jbuck