Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!jk3k+
From: jk3k+@andrew.cmu.edu (Joe Keane)
Newsgroups: comp.arch
Subject: Re: DECSYSTEM 20
Message-ID: <cYpQ1UW00VoBE9OFsn@andrew.cmu.edu>
Date: 1 Aug 89 15:23:12 GMT
References: <3256@wpi.wpi.edu> <EGDORF.89Jul21195924@zaphod.lanl.gov> <443@anasaz.UUCP> <BRUCE.89Jul23155646@heather.pooh.com> <3893@phri.UUCP> <433@scr1.UUCP> <976@mplvax.EDU>,
	<441@scr1.UUCP>
Organization: Mathematics, Carnegie Mellon, Pittsburgh, PA
Lines: 5
In-Reply-To: <441@scr1.UUCP>

The 11 has its registers in _physical_ memory.  This is too bad, since user
programs can't take advantage of it unless they have access to a lot of other
things.  But you can do a lot in 7 words.  I bet you could set up the memory
mapping so that the address of the PC is a useful instruction.  I've heard of a
lot of tricks, but never executing the PC...