Article View: comp.arch
Article #1646Re: DECSYSTEM 20
From: Roy Smith
Date: Tue, 25 Jul 1989 02:51
Date: Tue, 25 Jul 1989 02:51
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In <BRUCE.89Jul23155646@heather.pooh.com> bruce@heather.pooh.com
(Bruce Robertson) writes:
> I like the way the PDP-11 treats the program counter as a general
> register. You can play a lot of tricks with that!
I always wanted to try (I don't know why I never did) using
auto-decrement mode on r7 (i.e. the pc). I wonder what would happen? A
tight 1-instruction infinite loop? Akin, but not as bad as, the famous GD
Nova and DEC-10 infinite-indirection loops, I guess.
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
{att,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@alanine.phri.nyu.edu
"The connector is the network"
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cmcl2!phri!roy From: roy@phri.UUCP (Roy Smith) Newsgroups: comp.arch Subject: Re: DECSYSTEM 20 Summary: Really about pdp-11 pc as gp reg Message-ID: <3893@phri.UUCP> Date: 25 Jul 89 02:51:21 GMT References: <3256@wpi.wpi.edu> <EGDORF.89Jul21195924@zaphod.lanl.gov> <443@anasaz.UUCP> <BRUCE.89Jul23155646@heather.pooh.com> Reply-To: roy@phri.UUCP (Roy Smith) Organization: Public Health Research Inst. (NY, NY) Lines: 14