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From: paul@unisoft.UUCP (Paul Campbell)
Newsgroups: net.lang.c,net.arch
Subject: Re: Time penalty for non-alignment on VAX/780
Message-ID: <434@unisoft.UUCP>
Date: Wed, 27-Mar-85 00:15:15 EST
Article-I.D.: unisoft.434
Posted: Wed Mar 27 00:15:15 1985
Date-Received: Tue, 2-Apr-85 00:01:49 EST
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Organization: UniSoft Systems, Berkeley
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Xref: watmath net.lang.c:4898 net.arch:1061


No .... the Vax does not (necessarily) read data from its cache 64 bits at a
time. What it does is fetch 64bits into cache from memory when a cache miss
occurs (the SBI is 64 bits wide). This is a good idea for several reasons, 
for instruction lookahead, data lookahead, and it makes the cache design a 
little easier not having to compare as many address lines.


			Paul Campbell ucbvax!unisoft!paul