Re: MISC - Stack Based vs. Register Based

Newsgroups	comp.lang.forth
Date	2013-04-02 11:17 -0700
References	<kj4vae$msi$1@dont-email.me>
Message-ID	<fb734da0-7a39-4d53-8e68-eb2895cd8643@googlegroups.com> (permalink)
Subject	Re: MISC - Stack Based vs. Register Based
From	the_gavino_himself <visphatesjava@gmail.com>

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On Friday, March 29, 2013 2:00:50 PM UTC-7, rickman wrote:
> I have been working with stack based MISC designs in FPGAs for some 
> 
> years.  All along I have been comparing my work to the work of others. 
> 
> These others were the conventional RISC type processors supplied by the 
> 
> FPGA vendors as well as the many processor designs done by individuals 
> 
> or groups as open source.
> 
> 
> 
> So far my CPUs have always ranked reasonably well in terms of speed, but 
> 
> more importantly to me, very well in terms of size and code density.  My 
> 
> efforts have shown it hard to improve on code density by a significant 
> 
> degree while simultaneously minimizing the resources used by the design. 
> 
>   Careful selection of the instruction set can both improve code density 
> 
> and minimize logic used if measured together, but there is always a 
> 
> tradeoff.  One can always be improved at the expense of the other.
> 
> 
> 
> The last couple of days I was looking at some code I plan to use and 
> 
> realized that it could be a lot more efficient if I could find a way to 
> 
> use more parallelism inside the CPU and use fewer instructions.  So I 
> 
> started looking at defining separate opcodes for the two primary 
> 
> function units in the design, the data stack and the return stack.  Each 
> 
> has its own ALU.  The data stack has a full complement of capabilities 
> 
> while the return stack can only add, subtract and compare.  The return 
> 
> stack is actually intended to be an "address" processing unit.
> 
> 
> 
> While trying to figure out how to maximize the parallel capabilities of 
> 
> these units, I realized that many operations were just stack 
> 
> manipulations.  Then I read the thread about the relative "cost" of 
> 
> stack ops vs memory accesses and I realized these were what I needed to 
> 
> optimize.  I needed to find a way to not use an instruction and a clock 
> 
> cycle for moving data around on the stack.
> 
> 
> 
> In the thread on stack ops it was pointed out repeatedly that very often 
> 
> the stack operands would be optimized to register operands, meaning they 
> 
> wouldn't need to do the stack ops at all really.  So I took a look at a 
> 
> register based MISC design.  Guess what, I don't see the disadvantage! 
> 
> I have pushed this around for a couple of days and although I haven't 
> 
> done a detailed design, I think I have looked at it enough to realize 
> 
> that I can design a register oriented MISC CPU that will run as fast, if 
> 
> not faster than my stack based design and it will use fewer 
> 
> instructions.  I still need to add some features like support for a 
> 
> stack in memory, in other words, pre-increment/post-decrement (or the 
> 
> other way around...), but I don't see where this is a bad design.  It 
> 
> may end up using *less* logic as well.  My stack design provides access 
> 
> to the stack pointers which require logic for both the pointers and 
> 
> muxing them into the data stack for reading.
> 
> 
> 
> I guess looking at other peoples designs (such as Chuck's) has changed 
> 
> my perspective over the years so that I am willing and able to do 
> 
> optimizations in ways I would not have wanted to do in the past.  But I 
> 
> am a bit surprised that there has been so much emphasis on stack 
> 
> oriented MISC machines which it may well be that register based MISC 
> 
> designs are also very efficient, at least if you aren't building them to 
> 
> service a C compiler or trying to match some ideal RISC model.
> 
> 
> 
> -- 
> 
> 
> 
> Rick

any low priced pc that can run firefox coming out with your chip?

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MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-03-29 17:00 -0400
  Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-03-29 21:43 +0000
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-03-29 20:28 -0400
      Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-03-31 18:34 +0000
        Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 09:54 -0400
          Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-02 17:20 +0000
            Re: MISC - Stack Based vs. Register Based David Brown <david@westcontrol.removethisbit.com> - 2013-04-03 09:12 +0200
    Re: MISC - Stack Based vs. Register Based Jon Elson <jmelson@wustl.edu> - 2013-04-01 15:11 -0500
  Re: MISC - Stack Based vs. Register Based AKE <assadebrahim2000@gmail.com> - 2013-03-29 18:19 -0700
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-03-30 18:50 -0400
      Re: MISC - Stack Based vs. Register Based Jecel <jecel@merlintec.com> - 2013-04-01 13:18 -0700
        Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 10:50 -0400
          Re: MISC - Stack Based vs. Register Based Jecel <jecel@merlintec.com> - 2013-04-02 23:39 -0700
            Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-03 09:54 -0400
              Re: MISC - Stack Based vs. Register Based Jecel <jecel@merlintec.com> - 2013-04-05 14:30 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 17:53 -0400
                Re: MISC - Stack Based vs. Register Based Jecel <jecel@merlintec.com> - 2013-04-06 13:27 -0700
                Re: MISC - Stack Based vs. Register Based Jecel <jecel@merlintec.com> - 2013-04-06 13:37 -0700
        Re: MISC - Stack Based vs. Register Based Paul Rubin <no.email@nospam.invalid> - 2013-04-07 15:21 -0700
          Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-08 01:24 -0400
            Re: MISC - Stack Based vs. Register Based Syd Rumpo <usenet@nononono.co.uk> - 2013-04-08 10:18 +0100
          Re: MISC - Stack Based vs. Register Based Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-08 04:18 -0500
  Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-03-30 08:20 +0100
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-03-30 19:00 -0400
      Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-03-31 13:20 +0200
  Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-03-30 17:54 -0400
    Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-03-31 09:11 +0200
      Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-01 20:10 -0400
        Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-02 00:54 +0000
          Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 13:31 -0400
            Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-02 19:03 +0000
        Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-02 08:25 +0200
          Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 13:33 -0400
        Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 13:26 -0400
          Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-03 20:34 -0400
            Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-04 02:07 +0000
              Re: MISC - Stack Based vs. Register Based albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-04 11:16 +0000
                Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-04 13:25 +0200
                Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-04 12:44 +0000
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-04 17:04 -0400
                Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-04 21:34 +0000
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-04 19:30 -0400
                Re: MISC - Stack Based vs. Register Based Mark Wills <markrobertwills@yahoo.co.uk> - 2013-04-05 00:41 -0700
                Re: MISC - Stack Based vs. Register Based Alex McDonald <blog@rivadpm.com> - 2013-04-04 15:30 -0700
                Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-04 23:15 +0000
                Re: MISC - Stack Based vs. Register Based Alex McDonald <blog@rivadpm.com> - 2013-04-04 17:26 -0700
                Re: MISC - Stack Based vs. Register Based albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-05 01:17 +0000
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 18:00 -0400
                Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-08 23:55 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-04 20:07 -0400
                Re: MISC - Stack Based vs. Register Based Mark Wills <markrobertwills@yahoo.co.uk> - 2013-04-05 00:51 -0700
                Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-05 14:31 +0200
                Re: MISC - Stack Based vs. Register Based Mark Wills <markrobertwills@yahoo.co.uk> - 2013-04-05 07:33 -0700
                Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-05 17:01 +0200
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 18:25 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-06 17:44 -0400
                Re: MISC - Stack Based vs. Register Based Brad Eckert <hwfwguy@gmail.com> - 2013-04-05 10:14 -0700
                Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-05 20:13 +0200
                Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-05 20:15 +0200
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 18:54 -0400
                Re: MISC - Stack Based vs. Register Based Brad Eckert <hwfwguy@gmail.com> - 2013-04-08 09:57 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-09 10:13 -0400
                Re: MISC - Stack Based vs. Register Based Brad Eckert <hwfwguy@gmail.com> - 2013-04-09 08:55 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-09 14:40 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 18:49 -0400
                Re: MISC - Stack Based vs. Register Based daveyrotten <danw8804@gmail.com> - 2013-04-09 13:02 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-09 16:07 -0400
                Re: MISC - Stack Based vs. Register Based daveyrotten <danw8804@gmail.com> - 2013-04-09 13:26 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-10 00:33 -0400
                Re: MISC - Stack Based vs. Register Based daveyrotten <danw8804@gmail.com> - 2013-04-10 07:08 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-10 10:13 -0400
                Re: MISC - Stack Based vs. Register Based Sieur de Bienville <morrimichael@gmail.com> - 2013-04-10 21:08 -0700
                Re: MISC - Stack Based vs. Register Based Paul Rubin <no.email@nospam.invalid> - 2013-04-10 22:47 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-11 16:32 -0400
                Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-18 06:23 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-18 17:06 -0400
                Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-05 17:33 +0000
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-06 17:37 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 18:08 -0400
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-06 17:32 -0400
                Re: MISC - Stack Based vs. Register Based Brian Davis <brimdavis@aol.com> - 2013-04-07 14:59 -0700
                Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-08 01:16 -0400
                Re: MISC - Stack Based vs. Register Based albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-08 09:52 +0000
            Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-03 22:42 -0400
            Re: MISC - Stack Based vs. Register Based Alex McDonald <blog@rivadpm.com> - 2013-04-04 16:07 -0700
              Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-05 04:10 +0000
                Re: MISC - Stack Based vs. Register Based Alex McDonald <blog@rivadpm.com> - 2013-04-04 23:49 -0700
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-02 12:04 -0400
      Re: MISC - Stack Based vs. Register Based "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-03 20:35 -0400
        Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-04 00:09 -0400
  Re: MISC - Stack Based vs. Register Based the_gavino_himself <visphatesjava@gmail.com> - 2013-04-02 11:17 -0700
  Re: MISC - Stack Based vs. Register Based Syd Rumpo <usenet@nononono.co.uk> - 2013-04-04 09:38 +0100
    Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-04 11:31 +0200
      Re: MISC - Stack Based vs. Register Based "Elizabeth D. Rather" <erather@forth.com> - 2013-04-04 08:36 -1000
        Re: MISC - Stack Based vs. Register Based Brad Eckert <hwfwguy@gmail.com> - 2013-04-05 10:21 -0700
          Re: MISC - Stack Based vs. Register Based "Elizabeth D. Rather" <erather@forth.com> - 2013-04-05 07:53 -1000
    Re: MISC - Stack Based vs. Register Based glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-04-04 12:49 +0000
      Re: MISC - Stack Based vs. Register Based Arlet Ottens <usenet+5@c-scape.nl> - 2013-04-04 15:02 +0200
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-04 18:57 -0400
  Re: MISC - Stack Based vs. Register Based AKE <assadebrahim2000@gmail.com> - 2013-04-05 15:29 -0700
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-05 19:32 -0400
      Re: MISC - Stack Based vs. Register Based anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-04-06 14:16 +0000
        Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-06 15:50 -0400
          Re: MISC - Stack Based vs. Register Based mhx@iae.nl (Marcel Hendrix) - 2013-04-07 01:33 +0200
            Re: MISC - Stack Based vs. Register Based AKE <assadebrahim2000@gmail.com> - 2013-04-07 02:57 -0700
              Re: MISC - Stack Based vs. Register Based stephenXXX@mpeforth.com (Stephen Pelc) - 2013-04-07 11:02 +0000
              Re: MISC - Stack Based vs. Register Based anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-04-07 13:51 +0000
                Re: MISC - Stack Based vs. Register Based "Elizabeth D. Rather" <erather@forth.com> - 2013-04-07 09:16 -1000
            Re: MISC - Stack Based vs. Register Based anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-04-07 14:13 +0000
              Re: MISC - Stack Based vs. Register Based mhx@iae.nl (Marcel Hendrix) - 2013-04-07 17:14 +0200
                Re: MISC - Stack Based vs. Register Based anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-04-07 15:31 +0000
            Re: MISC - Stack Based vs. Register Based Bernd Paysan <bernd.paysan@gmx.de> - 2013-04-08 18:53 +0200
          Re: MISC - Stack Based vs. Register Based anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-04-07 14:22 +0000
  Re: MISC - Stack Based vs. Register Based "WJ" <w_a_x_man@yahoo.com> - 2013-04-14 00:19 +0000
    Re: MISC - Stack Based vs. Register Based rickman <gnuarm@gmail.com> - 2013-04-14 09:44 -0400
    Re: MISC - Stack Based vs. Register Based Brad Eckert <hwfwguy@gmail.com> - 2013-04-15 09:39 -0700
      Re: MISC - Stack Based vs. Register Based Bernd Paysan <bernd.paysan@gmx.de> - 2013-04-15 19:28 +0200

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