Re: Looking for a garbage collection paper

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From	gah4 <gah4@u.washington.edu>
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Subject	Re: Looking for a garbage collection paper
Date	Thu, 29 Sep 2022 23:56:42 -0700 (PDT)
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On Thursday, September 29, 2022 at 9:40:59 PM UTC-7, gah4 wrote:

(snip)

> But not if index registers are different from other registers, like
> (if I remember) they are on the 7090.

> [Yes, the 704 series had separate index registers. It occurs to me that
> another way to do this is to use the rotate instructions the 70x and PDP-6/10
> had. Since the word is 36 bits, you rotate by 12 each time and you'll have
> three bit patterns. -John]

or a ROTC double word rotate on the PDP-10 by 24, with 18 bit addressing
and indexing.

I am not sure about rotate on the 709 or 7090.

Also, for those machines, I suspect a 12 bit shift or rotate takes 12 cycles.
They didn't have enough logic for a barrel shifter, like many machines now have.
Might be slower than more than one fast instruction.
[The 709x had a rotate instruction but this archaeology is a bit far from compilers. -John]

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Looking for a garbage collection paper Spiros Bousbouras <spibou@gmail.com> - 2022-09-20 09:29 +0000
  Re: Looking for a garbage collection paper Robert Prins <robert@prino.org> - 2022-09-21 09:42 +0000
    Re: Looking for a garbage collection paper Spiros Bousbouras <spibou@gmail.com> - 2022-09-23 16:38 +0000
      Re: Looking for a garbage collection paper gah4 <gah4@u.washington.edu> - 2022-09-23 12:33 -0700
        Re: Looking for a garbage collection paper Thomas Koenig <tkoenig@netcologne.de> - 2022-09-29 13:15 -0400
          Re: Looking for a garbage collection paper gah4 <gah4@u.washington.edu> - 2022-09-29 21:10 -0700
            Re: Looking for a garbage collection paper gah4 <gah4@u.washington.edu> - 2022-09-29 23:56 -0700
  Re: Looking for a garbage collection paper drb@ihatespam.msu.edu (Dennis Boone) - 2022-09-23 19:39 +0000

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