Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation
Date	2013-07-04 12:22 -0700
Organization	Nightsong/Fort GNOX
Message-ID	<7x38ruxh8o.fsf@ruckus.brouhaha.com> (permalink)
References	(16 earlier) <kr3ss9$aok$1@dont-email.me> <7xppuy1ce1.fsf@ruckus.brouhaha.com> <kr49qb$jia$1@dont-email.me> <7x1u7e6xg8.fsf@ruckus.brouhaha.com> <kr4b85$t1o$1@dont-email.me>

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rickman <gnuarm@gmail.com> writes:
>> the effect is in principle 4x worse for a 32-bit adder
> You don't use MCUs like anyone else I know.  You look at the data they
> provide which is *chip* data.  No one provides power data separately
> for each logic function on an MCU.  So there is no way to analyze the
> device in this manner.

MCUs are not made out of magic--they use well-understood design and fab
processes and the designers know how to estimate these numbers and in
principle we could do the same.  Without actual numbers we can still
hopefully agree that it's bloody obvious that if two chips are made with
the same process and one of them has 4x more circuitry than the other,
the bigger one is likely to have more total leakage current than the
smaller one.  That's all I'm saying here.

>> Lack of code space, lack of ram, awkward instruction set, no compilers.
> These things (the few that are accurate...

Which of "lack of code space", "lack of ram", "awkward instruction set",
and "no compilers" are inaccurate?

> most of what you said about the GA144 is wrong) are limitations to you
> because you have not learned how to use the chip.  That is what I
> said.  You can't use any device until you learn how.  

I look at the sample code that GA has posted, and the pain level
apparent in that code, and I can only conclude that nobody knows how.

> You have already learned how to use conventional MCUs so you have
> already climbed up the learning curve.  Now you need to climb the
> learning curve for this device.

That sounds like a platitude.  Look at that conference paper on the GA
site, where somebody spent months programming the AES encryption
function onto something like 100 cores of a GA144.  Or the GA app note
about MD5, again taking months and spread across dozens of cores.  Both
those algorithms can easily be coded on a conventional MCU in an
afternoon.

> The GA144 is not inherently difficult to use for simple tasks.  In
> fact, I find it much easier to use than most MCUs where you often have
> to figure out how to use a single CPU to do multiple asynchronous
> tasks, interrupts, multi-threading, etc... not simple stuff to the
> uninitiated.

Let's take a fairly simple conceptual exercise and say you want to make
a typical, slightly fancy digital wrist watch.  Ignore the notorious
hardware issues of clocking the GA144 with a crystal, and assume you
have a precise 1000 hz timer toggling an input pin, and enough i/o pins
for all the LCD segments.  So you have to count these timer events, and
drive an LCD display showing the current time (hours/minutes/seconds),
day of the week, and calendar day.  You have to support a pushbutton UI
allowing setting the time and date, and you have to calculate the
weekday from the day/month/year, which requires taking leap years into
account.  You want stopwatch and alarm functions, but we'll skip unusual
features like the sunrise/sunset time or moon phase.  I have a $5 watch
that does all this stuff, so it's not outlandish.

How would you envision the GA144 code for this being organized?  On a
conventional MCU it's all very straightforward coding.  You might want
to use interrupts, or you could do a single threaded polling loop.
MCU's usually have built-in counter/timers so you can let the hardware
divide the 1000 hz down to 1 hz for display update.  The only catch is
that there's enough functions that you might need a KB or so of code.
On an MCU that's no big deal.  On the GA144 it means having to split the
code across many different cores, and deal with routing communications
around between the cores, etc.  Plus you have to program in a very low
level Forth subset.  MCU's usually have C compilers, or (this being clf)
full featured ANS Forth which we can consider to be about equivalent.

It's pretty clear that if you make any realistic plan in your head about
how you'd develop the code for the two approaches, the coding hassle is
just much, much lower with the MCU.

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Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-06-24 11:02 +0200
  Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-06-24 05:54 -0700
    Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-06-25 10:51 +0200
      Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-06-25 02:29 -0700
        Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-06-25 14:06 +0200
          Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-06-25 10:34 -0700
            Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-06-26 11:03 +0200
              Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-06-26 22:18 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-06-27 12:09 +0200
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-06-27 11:15 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-06-27 09:55 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-06-27 15:02 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation visualforth@rocketmail.com - 2013-06-30 21:43 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-01 12:09 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-01 16:44 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-01 18:14 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-02 10:36 +0200
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Mark Wills <markrobertwills@yahoo.co.uk> - 2013-07-02 03:12 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-02 10:17 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-02 16:35 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-02 16:33 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-03 00:51 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-03 10:38 +0200
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-04 09:26 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-04 10:08 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-04 13:07 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-04 10:34 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-04 13:31 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-04 12:22 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-04 12:27 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-05 17:05 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-05 15:09 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-05 19:21 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-05 17:49 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-06 00:38 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-05 22:39 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-06 10:56 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-06 20:35 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-07 10:44 +0000
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-07 12:48 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-07 01:20 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-08 11:49 +0200
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation rickman <gnuarm@gmail.com> - 2013-07-08 09:55 -0400
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Roberto Waltman <usenet@rwaltman.com> - 2013-07-06 12:48 -0400
          Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-08 14:47 +0200
            Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-08 09:37 -0700
            Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation stephenXXX@mpeforth.com (Stephen Pelc) - 2013-07-09 11:32 +0000
              Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-09 14:27 +0200
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Bill Richards <billrich@gmx.com> - 2013-07-09 13:41 +0000
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-09 09:23 -0500
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-10 02:27 +0000
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Bill Richards <billrich@gmx.com> - 2013-07-10 07:34 +0000
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-10 03:18 -0500
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Paul Rubin <no.email@nospam.invalid> - 2013-07-10 01:43 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Brad Eckert <hwfwguy@gmail.com> - 2013-07-16 08:31 -0700
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-10 03:02 -0500
                Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation stephenXXX@mpeforth.com (Stephen Pelc) - 2013-07-09 15:14 +0000
      Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation visualforth@rocketmail.com - 2013-07-15 12:27 -0700
        Re: Announcing Mecrisp-Stellaris - a native code ARM-Cortex implementation Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2013-07-16 11:52 +0200

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