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Re: Indirect Bit

Message-ID <4F87AE90.1000209@SPAM.comp-arch.net> (permalink)
Date 2012-04-12 21:41 -0700
From "Andy (Super) Glew" <andy@SPAM.comp-arch.net>
Organization comp-arch.net
Newsgroups comp.arch
Subject Re: Indirect Bit
References <4F84FB1E.6CD1FC88@sonic.net> <4F86ECC6.4060405@SPAM.comp-arch.net> <7207568.240.1334250963776.JavaMail.geo-discussion-forums@yncd8> <jm77ab$50m$1@dont-email.me>

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On 4/12/2012 11:35 AM, Stephen Fuld wrote:
> On 4/12/2012 10:16 AM, MitchAlsup wrote:
>> On Thursday, April 12, 2012 9:55:02 AM UTC-5, Andy (Super) Glew wrote:
>>> The indirect bit is not good enough. Too simplistic. Definitely need
>>> to talk about adding offsets, and possibly searches for particular data
>>> patterns. Since I have never seen or come up with a reasonably
>>> satisfactory set, I fall down the slipper slope to some simple
>>> instruction packet.
>>
>> I believe that the S.E.L (n.e. Gould) 32 architecture supports
>> indirection.
>> In this case, the data loaded from memory contains not just an
>> indirect bit
>> but also another base register, and an offset so one could "do clever
>> things".
>
> The Univac 1108 and its successors have an indirect bit in each
> instruction that has a memory address and the indirection includes not
> only the address and another indirect bit, but an index register and
> even a bit that indicates index register incrementation. So you could
> really could "do clever things", especially once you realize that
> control instructions such as jump to the address given in the
> instruction could be indirected as well. This allowed for some *really*
> clever things.

This is cool - I had forgotten about the SEL indirection, which really 
was not an indirection, more like an "execute instruction at this memory 
location".  Heck, I've still forgotten - I remember "execute instruction 
in register", and maybe in memory. Perhaps execute instruction in memory 
could be another execute instruction in memory, and so on.

(By the way, note: execute-instruction-in-memory is a special 
instruction, not just a load-word that looks for the indirect bit.)

But it also reveals the problem: execute-instruction-in-memory is easy 
if the memory location is fetched to the procewssor, and then executed 
by the processor, where it has access to all the processor state.

However, if you want to export it so that it is done outside the 
processor, how much state do you send?  The entire register set?  :-(
A bitmask indicating what registers to send? :-(

By now we are almost at an instruction packet - because if we send 
multiple registers, surely we would want to do multiple instructions? 
If only to build large constants on a RISC machine (not on a variable 
width ISA with full width constants.)

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Indirect Bit Mark Thorson <nospam@sonic.net> - 2012-04-10 19:31 -0800
  Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-11 01:29 -0500
    Re: Indirect Bit sarr.blumson@alum.dartmouth.org - 2012-04-11 14:48 +0000
      Re: Indirect Bit mac <acolvin@efunct.com> - 2012-04-12 14:43 +0000
    Re: Indirect Bit Morten Reistad <first@last.name> - 2012-04-22 15:19 +0200
      Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-22 23:24 -0700
  Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-11 08:32 +0200
    Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-11 05:49 -0700
      Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 21:22 -0700
        Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-13 08:14 -0700
          Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-13 16:13 -0700
            Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-13 20:01 -0700
              Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-14 03:16 +0000
                Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-14 08:14 -0700
        Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-13 16:05 -0700
          Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-13 17:01 -0700
            Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-14 13:49 -0700
          Re: Indirect Bit Anne & Lynn Wheeler <lynn@garlic.com> - 2012-04-13 20:07 -0400
          Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-14 18:47 +0200
          Re: Indirect Bit Morten Reistad <first@last.name> - 2012-04-22 15:26 +0200
            Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-22 23:25 -0700
              Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-23 09:18 +0100
                Re: Indirect Bit EricP <ThatWouldBeTelling@thevillage.com> - 2012-04-23 19:35 -0400
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-24 08:37 +0100
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-24 09:42 +0100
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-24 01:58 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-24 11:26 +0100
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-24 05:02 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-24 13:58 +0100
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-24 10:07 -0700
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-24 04:30 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-24 13:01 +0100
  Re: Indirect Bit Stefan Monnier <monnier@iro.umontreal.ca> - 2012-04-11 10:03 -0400
  Re: Indirect Bit kenney@cix.compulink.co.uk - 2012-04-11 09:22 -0500
    Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-12 14:11 -0700
      Re: Indirect Bit Stefan Monnier <monnier@iro.umontreal.ca> - 2012-04-12 18:05 -0400
        Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 20:13 -0700
      Re: Indirect Bit Mark Thorson <nospam@sonic.net> - 2012-04-12 16:55 -0800
        Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-12 17:25 -0700
          Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-12 20:03 -0500
          Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 21:33 -0700
            Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-13 15:57 -0700
              Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-13 17:03 -0700
        Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 20:14 -0700
  Re: Indirect Bit Anne & Lynn Wheeler <lynn@garlic.com> - 2012-04-11 10:35 -0400
  Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-11 08:54 -0700
  Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 07:55 -0700
    Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-12 10:16 -0700
      Re: Indirect Bit jacko <jackokring@gmail.com> - 2012-04-12 11:07 -0700
        Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 21:34 -0700
      Re: Indirect Bit Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2012-04-12 11:35 -0700
        Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 21:41 -0700
          Re: Indirect Bit jacko <jackokring@gmail.com> - 2012-04-13 14:52 -0700
          Re: Indirect Bit Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2012-04-15 09:24 -0700
            Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-15 22:45 +0200
              Re: Indirect Bit Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2012-04-15 18:04 -0700
      Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-12 21:12 -0700
    Re: Indirect Bit timcaffrey@aol.com (Tim McCaffrey) - 2012-04-12 19:23 +0000
    Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-13 08:54 +0200
      Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-14 14:37 -0700
    Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-15 23:42 +0000
      Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-16 08:08 -0700
        Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-16 23:38 +0000
          Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-16 21:29 -0700
      Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-16 21:25 -0700
  Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-12 14:05 -0700
    Re: Indirect Bit ChrisQ <blackhole@devnull.com> - 2012-04-14 10:12 +0000
      Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-14 06:25 -0700
        Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-14 14:50 +0100
          Re: Indirect Bit ChrisQ <blackhole@devnull.com> - 2012-04-14 18:01 +0000
            Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-14 14:00 -0700
              Re: Indirect Bit Anne & Lynn Wheeler <lynn@garlic.com> - 2012-04-14 20:58 -0400
            Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-16 09:57 -0700
            Re: Indirect Bit timcaffrey@aol.com (Tim McCaffrey) - 2012-04-20 23:19 +0000
          Re: Indirect Bit "Paul A. Clayton" <paaronclayton@gmail.com> - 2012-04-16 08:50 -0700
            Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-16 18:09 +0100
              Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-16 23:19 +0000
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-17 09:20 +0100
                Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-17 12:49 +0200
                Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-17 12:40 +0000
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-18 12:01 +0100
                Re: Indirect Bit anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-04-17 12:34 +0000
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-17 09:10 -0700
                Re: Indirect Bit Andrew Reilly <areilly.---@bigpond.net.au> - 2012-04-17 22:05 +0000
                Re: Indirect Bit jgk@panix.com (Joe keane) - 2012-04-19 19:37 +0000
                Re: Indirect Bit torbenm@diku.dk (Torben Ægidius Mogensen) - 2012-04-20 11:10 +0200
                Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-20 11:24 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-20 15:01 +0100
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-20 15:03 +0100
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-20 08:01 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-20 16:35 +0100
                Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-18 11:10 -0700
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-18 15:37 -0700
          Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-16 11:21 -0700
            Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-16 19:36 +0100
              Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-18 11:17 -0700
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-18 15:33 -0700
                Re: Indirect Bit Andreas Eder <andreas_eder@gmx.net> - 2012-04-19 00:29 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-19 10:50 +0100
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-19 11:29 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-19 21:39 +0100
                Re: Indirect Bit EricP <ThatWouldBeTelling@thevillage.com> - 2012-04-20 15:14 -0400
                Re: Indirect Bit "Andy (Super) Glew" <andy@SPAM.comp-arch.net> - 2012-04-20 22:43 -0700
                Re: Indirect Bit EricP <ThatWouldBeTelling@thevillage.com> - 2012-04-21 17:14 -0400
                Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-21 19:47 -0500
                Re: Indirect Bit Nomen Nescio <nobody@dizum.com> - 2012-04-22 10:45 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-22 09:57 +0100
                Re: Indirect Bit Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-22 12:54 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-22 13:00 +0100
                Re: Indirect Bit Nomen Nescio <nobody@dizum.com> - 2012-04-22 13:28 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-22 13:04 +0100
                Re: Indirect Bit Fritz Wuehler <fritz@spamexpire-201204.rodent.frell.theremailer.net> - 2012-04-22 23:00 +0200
                Re: Indirect Bit Anne & Lynn Wheeler <lynn@garlic.com> - 2012-04-22 18:05 -0400
                Re: Indirect Bit glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-04-22 23:20 +0000
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-23 08:22 +0100
                Re: Indirect Bit Michael S <already5chosen@yahoo.com> - 2012-04-22 03:56 -0700
                Re: Indirect Bit EricP <ThatWouldBeTelling@thevillage.com> - 2012-04-22 12:28 -0400
                Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-22 12:56 -0500
                Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-22 13:15 -0700
                Re: Indirect Bit Nomen Nescio <nobody@dizum.com> - 2012-04-22 22:30 +0200
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-22 21:40 +0100
                Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-22 17:15 -0500
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-23 08:26 +0100
                Re: Indirect Bit Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2012-04-23 08:02 -0700
                Re: Indirect Bit nmm1@cam.ac.uk - 2012-04-23 17:02 +0100
                Re: Indirect Bit Fritz Wuehler <fritz@spamexpire-201204.rodent.frell.theremailer.net> - 2012-04-23 20:17 +0200
                Re: Indirect Bit Robert Wessel <robertwessel2@yahoo.com> - 2012-04-23 13:07 -0500
                Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-22 13:16 -0700
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-23 13:14 -0700
                Re: Indirect Bit Anne & Lynn Wheeler <lynn@garlic.com> - 2012-04-23 16:51 -0400
                Re: Indirect Bit Quadibloc <jsavard@ecn.ab.ca> - 2012-04-23 14:22 -0700
                Re: Indirect Bit MitchAlsup <MitchAlsup@aol.com> - 2012-04-21 11:17 -0700
        Re: Indirect Bit jacko <jackokring@gmail.com> - 2012-04-14 08:02 -0700

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