Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!microsoft!gideony
From: gideony@microsoft.UUCP (Gideon YUVAL)
Newsgroups: comp.arch
Subject: Re: Is handling off-alignment important?
Message-ID: <56353@microsoft.UUCP>
Date: 7 Aug 90 00:29:29 GMT
References: <104037@convex.convex.com> <8840014@hpfcso.HP.COM> <2357@crdos1.crd.ge.COM> <25900@mimsy.umd.edu>
Reply-To: gideony@microsoft.UUCP (Gideon YUVAL)
Organization: Microsoft Corp., Redmond WA
Lines: 20

In article <25900@mimsy.umd.edu> chris@mimsy.umd.edu (Chris Torek) writes:
>In article <2357@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.COM
>(Wm E Davidsen Jr) writes:
... ... ... ... ... ... ... ... ... ... ...  > Consider the
>following VAX gem:

>	addl3	*0(r1),*0(r2),*0(r3)
...
> total 14 pages for one `simple' `addl3' instruction.

>(Imagine the fun with a six-argument instruction like `index'!)

I'm told this is why the VAX has a 512-byte page -- a 128KB box
was planned (but never made), and in the worst-case (an instruction
straddling 40 pages), would have deadlocked at <40 pages available.

The page-size thus had to be less than one-fortieth of the page-list
of a bare-minimum (1977!) system. 
-- 
Gideon Yuval, gideony@microsof.UUCP, 206-882-8080 (fax:206-883-8101;TWX:160520)