Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!mailrus!nrl-cmf!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: The D Programming Language (was: Still more new operators)
Message-ID: <7414@brl-smoke.ARPA>
Date: 4 Mar 88 13:14:09 GMT
References: <11702@brl-adm.ARPA> <243@eagle_snax.UUCP> <2245@geac.UUCP> <1988Mar3.182645.703@utzoo.uucp>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 13

In article <1988Mar3.182645.703@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>I once had the opportunity to ask Bill Wulf what he thought of bit-oriented
>machines; his answer was "I wish they weren't so damned slow".  I'm afraid
>I haven't seen anything since that invalidates that assessment.  There is
>something to be said for providing bit addressability, but one must realize
>that actually exploiting it will be slow and that there will still be a
>large payoff for trying to work on byte or word boundaries whenever possible.

Bit-addressable architectures need not be slow; you could apply the same line
of reasoning to "prove" that byte-addressability makes a machine too slow,
but of course they aren't necessarily slow.  The main trick to is handle most
operations at a large alignment and revert to bit accesses only when called
for, in which case they will certainly be faster than the corresponding code
on an equivalent non bit-addressable architecture.