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From: garry@batcomputer.TN.CORNELL.EDU (Garry Wiegand)
Newsgroups: net.unix-wizards
Subject: Re: brk's zero-fill behavior on VAXen
Message-ID: <1375@batcomputer.TN.CORNELL.EDU>
Date: Mon, 3-Nov-86 22:46:09 EST
Article-I.D.: batcompu.1375
Posted: Mon Nov  3 22:46:09 1986
Date-Received: Tue, 4-Nov-86 08:47:01 EST
Reply-To: garry%cadif-oak@cu-arpa.cs.cornell.edu
Organization: Cornell Engineering && Flying Moose Graphics
Lines: 13

In a recent article hope@gatech.UUCP (Theodore Hope) wrote:
>In article <7208@elsie.UUCP> ado@elsie.UUCP (Arthur David Olson) writes:
>>Can system performance be improved by avoiding zero filling of the new
>>memory?
>
>It can be assumed that on many architectures (such as the Vax) the process
>of zero-filling a block of memory can be done in one or a few instructions.

"One or a few" is not a meaningful criterion. The Vax's MOVC5 instruction
is indeed a single instruction - but it runs at just about the same speed
as an equivalent sequence of CLRL (reg)+ instructions.

garry wiegand   (garry%cadif-oak@cu-arpa.cs.cornell.edu)