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Re: double tasking with two interpreters

Date 2012-05-27 18:38 -1000
From "Elizabeth D. Rather" <erather@forth.com>
Organization FORTH, Inc.
Newsgroups comp.lang.forth
Subject Re: double tasking with two interpreters
References <7xmx4tckcg.fsf@ruckus.brouhaha.com> <9KmdnfHCls1fIl_SnZ2dnUVZ_gidnZ2d@supernews.com> <7xtxz19jg8.fsf@ruckus.brouhaha.com>
Message-ID <m7adnXmFXo7HnF7SnZ2dnUVZ_t6dnZ2d@supernews.com> (permalink)

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On 5/27/12 3:35 PM, Paul Rubin wrote:
> "Elizabeth D. Rather"<erather@forth.com>  writes:
>> Well, I think there are simpler ways. Assume you have one register
>> (called U) pointing to the status area of the "current" user or task,
>> and one register each for the current task's S and R.
>
> OK, but now you no longer have the optimizations of keeping TOS and the
> instruction pointer in registers, most of the machine registers are
> being left unused, and you're consuming more memory with that stuff that
> could have been in registers.  Avoiding all that was the idea of having
> a separate register subset for each task.

You can certainly keep TOS in a register... just one more thing to push 
on the stack and pop off again (1 instruction each). As for I, it is set 
from the top of the return stack when a task wakes up.

And the rest of the machine registers are hardly "unused" -- they're 
available for the code that's running.

When we're addressing the task of implementing Forth on a new processor, 
register allocation and usage is the first and most important 
consideration in the design. I suggest that you download the SwiftX 
evaluation version for the MSP430 and spend some time reading the 
manual, in the parts that describe register utilization and the 
multitasker.  It'll give you a lot of ideas. That is, of course, a cross 
compiler, but as I recall it can run an interpreter in the target.

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
applications since 1973."
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double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-27 15:47 -0700
  Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-27 13:58 -1000
    Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-27 18:35 -0700
      Re: double tasking with two interpreters BruceMcF <agila61@netscape.net> - 2012-05-27 20:14 -0700
      Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-27 18:38 -1000
  Re: double tasking with two interpreters "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-28 12:08 -0400
    Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-28 09:21 -0700
      Re: double tasking with two interpreters BruceMcF <agila61@netscape.net> - 2012-05-28 10:11 -0700
      Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-28 07:24 -1000
        Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-28 11:11 -0700
          Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-28 11:23 -1000
            Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-28 14:36 -0700
              Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-28 12:52 -1000
                Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-28 17:14 -0700
                Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-28 15:33 -1000
                Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-28 18:53 -0700
                Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-28 22:34 -1000
                Re: double tasking with two interpreters Dirk Bruehl <dirk.bruehl@usa.net> - 2012-05-29 14:57 -0700
          Re: double tasking with two interpreters Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-29 22:16 +0200
            Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-29 10:57 -1000
              Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-29 14:23 -0700
        Re: double tasking with two interpreters Rugxulo <rugxulo@gmail.com> - 2012-05-29 00:22 -0700
    Re: double tasking with two interpreters "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-28 12:42 -0400
      Re: double tasking with two interpreters "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-28 13:07 -0400
        Re: double tasking with two interpreters Coos Haak <chforth@hccnet.nl> - 2012-05-28 21:39 +0200
      Re: double tasking with two interpreters Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-29 12:56 +0000
    Re: double tasking with two interpreters Bernd Paysan <bernd.paysan@gmx.de> - 2012-05-29 22:12 +0200
  Re: double tasking with two interpreters anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-05-29 08:19 +0000
  Re: double tasking with two interpreters stephenXXX@mpeforth.com (Stephen Pelc) - 2012-05-29 11:52 +0000
    Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-29 11:17 -0700
      Re: double tasking with two interpreters stephenXXX@mpeforth.com (Stephen Pelc) - 2012-05-29 20:15 +0000
        Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-30 09:12 -0700
          Re: double tasking with two interpreters Dirk Bruehl <dirk.bruehl@usa.net> - 2012-05-30 20:20 -0700
    Re: double tasking with two interpreters Dirk Bruehl <dirk.bruehl@usa.net> - 2012-05-29 11:25 -0700
  Re: double tasking with two interpreters Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-29 12:52 +0000
    Re: double tasking with two interpreters stephenXXX@mpeforth.com (Stephen Pelc) - 2012-05-29 13:29 +0000
      Re: double tasking with two interpreters BruceMcF <agila61@netscape.net> - 2012-05-29 08:29 -0700
      Re: double tasking with two interpreters John Passaniti <john.passaniti@gmail.com> - 2012-05-29 14:24 -0700
        Re: double tasking with two interpreters Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-30 01:59 -0700
          Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-30 03:05 -0700
            Re: double tasking with two interpreters Mark Wills <markrobertwills@yahoo.co.uk> - 2012-05-30 03:19 -0700
              Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-30 08:24 -0700
          Re: double tasking with two interpreters John Passaniti <john.passaniti@gmail.com> - 2012-05-30 07:20 -0700
            Re: double tasking with two interpreters Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-31 11:32 +0000
              Re: double tasking with two interpreters John Passaniti <john.passaniti@gmail.com> - 2012-06-01 07:07 -0700
    Re: double tasking with two interpreters "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-29 11:55 -0400
      Re: double tasking with two interpreters "Elizabeth D. Rather" <erather@forth.com> - 2012-05-29 08:23 -1000
    Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-29 11:39 -0700
      Re: double tasking with two interpreters BruceMcF <agila61@netscape.net> - 2012-05-29 12:26 -0700
      Re: double tasking with two interpreters Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-30 09:34 +0000
        Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-30 03:02 -0700
          Re: double tasking with two interpreters Arnold Doray <invalid@invalid.com> - 2012-05-30 14:10 +0000
            Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-30 08:34 -0700
              Re: double tasking with two interpreters Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-05-31 11:44 +0000
                Re: double tasking with two interpreters Alex McDonald <blog@rivadpm.com> - 2012-05-31 07:02 -0700
          Re: double tasking with two interpreters BruceMcF <agila61@netscape.net> - 2012-05-31 07:17 -0700
    Re: double tasking with two interpreters David Kuehling <dvdkhlng@gmx.de> - 2012-05-31 10:09 +0200
      Re: double tasking with two interpreters Paul Rubin <no.email@nospam.invalid> - 2012-05-31 02:07 -0700

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