<div dir="ltr"><div>Patrick,</div><div><br></div><div>Thanks for the tips!</div><div><br></div><div>Yes please email me the old thread, at my address below. </div><div><br></div><div>Likewise any tips you gained from Lua. Was Lua running from ROM? Did it use known-length strings inside the interp?</div><div><br></div><div>STM32 is a big product line. Its capabilities are pretty typical of all ARM microcontrollers. I guess STM32 is so popular it's practically setting the bar for ARM MCU's these days. The F4 series has a parallel external memory bus called FSMC, but I'm not using it on this project. It would really help. SPI RAM chips are available but I expect they'd be too slow for Jim's big demand on memory bandwidth and random address access.</div><div><br></div><div>I should have made it clear; I'm running Jim on bare metal here, no OS at all. Often I find an OS/RTOS to be more trouble than it's worth.</div><div><br></div><div>World: "It doesn't sound possible."</div><div>TheMarkitecht: "Dude, hold my Cheetos..." </div><div>(bangs away furiously at keyboard)</div><div dir="ltr"><br></div><div>I've had Jim running on bare metal for several weeks now. At this point I'm running strictly the core (jim.c). Most of the modular functionality like file systems is meaningless in a bare metal environment. So I shut that off right away. Eventually I'll bring back whichever pieces make sense there. At one point I had turned on Jim references, and regex, to try out Slim OOP on it (<a href="https://github.com/TheMarkitecht/slim">https://github.com/TheMarkitecht/slim</a>). But alas, that will need more RAM. Maybe more will become available if I can run directly from flash with known-length strings.</div><div dir="ltr"><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><p class="MsoNormal" style="color:rgb(34,34,34)">--<br><a href="mailto:TheMarkitecht@gmail.com" target="_blank">TheMarkitecht@gmail.com</a><u></u></p><p class="MsoNormal" style="color:rgb(34,34,34)"><span style="color:black">"GUI: (noun) - a method of organizing all my console windows."</span></p><p class="MsoNormal" style="color:rgb(34,34,34)"><br></p><p class="MsoNormal" style="color:rgb(34,34,34)">Slim OOP for Jim Tcl: <a href="https://github.com/TheMarkitecht/slim" target="_blank">https://github.com/TheMarkitecht/slim</a><span style="color:black"><br></span></p><p class="MsoNormal" style="color:rgb(34,34,34)"><br></p></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Feb 3, 2021 at 7:01 AM Patrick <<a href="mailto:patrick@spellingbeewinnars.org">patrick@spellingbeewinnars.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>On 2021-02-02 4:50 p.m., Patrick wrote:<br>
</div>
<blockquote type="cite">
<div>On 2021-01-31 2:57 p.m., Mark H
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hey guys,
<div><br>
</div>
<div>I have a small project with Jim on an STM32F4
microcontroller. It has about 104 KB RAM available to the
app. That actually works pretty well, and can navigate its
UI on a 20x4 character LCD. I expect to use Jim on other
MCU projects as well.</div>
<div><br>
</div>
<div>Predictably, it's starting to have serious RAM-cram. So
I've been looking at ways to run scripts directly from where
they reside in flash (effectively ROM). That way the entire
application script (plus Jim stdlib) doesn't get copied to
RAM before it even begins interpreting. And then each proc
body copied to more RAM etc. </div>
<div><br>
</div>
<div>So, some open questions:</div>
<div><br>
</div>
<div>1) Has anybody else tried something similar? How did
you approach it and how well did it work?</div>
<div><br>
</div>
<div>2) I've tried a few approaches so far. Each of those
has "almost" run correctly. The basic problem is that Jim's
(0.79) hashtables and certain other functions rely on
null-terminated strings. They discard or ignore the (in
most cases) known length of the string. But those nulls are
not present when (for example) command or variable name
tokens point to ROM instead of RAM, because I've shut off
the strdup that would have made the RAM copy. The original
script in ROM has the remainder of the script where the
interp is expecting the null to be. I've tracked down and
fixed those issues in a few important functions, but
certainly not all. I've gotten a few lines of script to run
that way, so it probably can work for the rest. It looks
like it might be a long road to complete that approach, and
would likely introduce bugs wherever i've missed a spot. I
have no obvious way to run Jim's test suite on such a small
host, and no obvious way to make scripts read-only on a PC
to run the tests there instead. So...</div>
<div><br>
</div>
<div>3) ...Instead, I'm starting to seriously consider a
comprehensive solution. Such as: throughout jim.c, replace
all char* function parameters with a new structure instead,
such as "Jim_Text", which carries both the char* and the
known length. That would mean basically a wholesale
paradigm shift from C-style strings to known-length
strings. You might say Pascal-style strings, but I wouldn't
store the length at the front of the string data like Pascal
does. That makes it too easy to overlook a piece of code
that needed the rework, introducing insidious bugs. The new
design should pass all existing test suites verbatim. And
it should be able to do so on a PC, where the tests are
available, proving that it's likely to also work on the MCU,
where tests aren't available.</div>
<div><br>
</div>
<div>4) Is anybody else interested in seeing that approach
adopted? There might be other benefits besides running
scripts from ROM. One benefit might be a bit faster
execution, since most strlen() calls or other null-byte
searches are eliminated. Currently those are happening
every time a hash key is computed, and in other hotspots.</div>
<div><br>
</div>
<div>5) I heard Steve mentioning recent improvements to make
Jim insensitive to nulls embedded in data. Anybody care to
guess how that work interplays with this approach?</div>
<div><br>
</div>
<div>6) Would anybody else be interested in helping with the
extensive rework?</div>
<div><br>
</div>
<div>7) Are there any Tcl TIP's, or Jim open issues, that
relate to my goal, or to this paradigm shift either?</div>
<div><br>
</div>
<div>Thanks for any clues!</div>
<div><br>
</div>
<div>--</div>
<div>TheMarkitecht</div>
<div>
<div dir="ltr"><span style="font-size:12.8px">"I'm always
disappointed when a liar's pants don't actually catch on
fire."</span><br>
</div>
<div dir="ltr"><a href="https://github.com/TheMarkitecht/slim" target="_blank">https://github.com/TheMarkitecht/slim</a><span style="font-size:12.8px"><br>
</span></div>
<div dir="ltr"><br>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
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</pre>
</blockquote>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p>Hi Mark</p>
<p>I am sure that Steve knows best with this but just for the
record, I have wanted to do something like this too. What OS are
you running? Even if the microcontroller has memory, is there
anything to stop us from using external memory? Perhaps over SPI
etc ..</p>
<p>BTW, if you do go down the Lua road, I was part of eLua and I
can tell you what I learned from this, just PM me.<br>
</p>
<p>-Pat<br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<br>
<fieldset></fieldset>
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</pre>
</blockquote>
<p>I just looked up the STM32F4 and it does not run RetroBSD. I am
not sure if you can squeeze Bertos or Contiki on it but it is
smaller than I thought.</p>
<p>I asked about running jim on baremetal once and there is a thread
about this if you want me to forward old emails. It does not sound
possible as so much of jim is tied to the OS.</p>
<p>Sorry for the noise everyone<br>
</p>
</div>
</blockquote></div></div>