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Re: No Promises

Message-ID <4E10B65B.4010104@SPAM.comp-arch.net> (permalink)
Date 2011-07-03 11:35 -0700
From "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net>
Organization comp-arch.net
Newsgroups comp.arch
Subject Re: No Promises
References (2 earlier) <0f148eb2-9bff-4694-b3dc-5c156db5491c@y27g2000prb.googlegroups.com> <1a518159-cd4e-4a8c-ace3-483612073616@22g2000prx.googlegroups.com> <eec31e07-5e9e-4260-a665-24efbdb5bcae@x1g2000yqb.googlegroups.com> <b5024b72-44a3-4398-8981-41d86e04d025@t19g2000yql.googlegroups.com> <aafb7b25-0df2-45e5-8e46-8e0171f1d37b@h17g2000yqn.googlegroups.com>

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On 7/3/2011 9:42 AM, Quadibloc wrote:
> On May 10, 6:56 pm, MitchAlsup<MitchAl...@aol.com>  wrote:
>
>> Also note: Back in 1980-83 I worked for S.E.L which became Gould
>> S.E.L. This company had a "good parts" of the 360 architecture encoded
>> in such a way that the low order bits of the address constant were
>> used to select the width of the data being loaded or stored (saving
>> ISA space)
>
> Incidentally, this particular idea, used on the SEL 32, so favorably
> impressed me that I used it - giving them credit, even - in my own
> fantasy ISA in order to reserve large expanses of opcode space for
> instructions that, in one way or another, would allow the computer to
> do more of its work with instructions that were only 16 bits long
> instead of 32 bits long.
>
> An example is at:
>
> http://www.quadibloc.com/arch/ar010002.htm
>
> John Savard


I think this is what you are talking about:

https://semipublic.comp-arch.net/wiki/Extra_bit_mask_trick


I encountered this when I joined Gould in 1985.  I had earlier used it 
in my undergraduate computer project.

I believe that I have found earlier references, but don't have them at 
hand to place in the wiki.

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Thread

No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-09 18:23 -0700
  Re: No Promises MitchAlsup <MitchAlsup@aol.com> - 2011-05-09 20:00 -0700
    Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-09 20:30 -0700
      Re: No Promises MitchAlsup <MitchAlsup@aol.com> - 2011-05-10 09:34 -0700
        Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-10 15:46 -0700
          Re: No Promises MitchAlsup <MitchAlsup@aol.com> - 2011-05-10 17:56 -0700
            Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-10 18:32 -0700
            Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-11 15:27 -0700
              Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-14 02:48 -0700
              Re: No Promises MitchAlsup <MitchAlsup@aol.com> - 2011-05-14 09:58 -0700
                Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-14 10:32 -0700
                Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-05-14 11:07 -0700
                Re: No Promises "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-05-14 17:07 -0700
            Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 09:42 -0700
              Re: No Promises "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 11:35 -0700
                Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 17:17 -0700
                Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 18:03 -0700
                Re: No Promises Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 09:31 -0700

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