[Coco] Bit-Banger Serial as external console?

[Joel Rees]

Forth and BASIC together, and trying to do something useful, without
an MMU, is going to take some careful work. It's a little like phone
booth stuffing, if you ever did that in college.

And Forth tends to play games in the code where the algorithm itself
depends on the relative locations and sizes of the pieces.

I'm trying to resurrect a "purely" fig Forth for the 6809, and I'm
finding that I played too loosely with the pieces without paying
attention to what they do. One of the early sins of Forth is the
tendency for the pieces to have lots of mutual dependencies, and that
is how they fit all the functionality in 64K of addressable memory.

On Fri, Mar 29, 2019 at 5:01 AM Stephen Pereira
<stephen.m.pereira.sr at gmail.com> wrote:
>
> Hi Dave,
>
> I took this off the CoCo list because it is definitely not associated with the original thread of using the Bit-Banger SIO port for a remote terminal…
>
> You seem to still be ignoring the documentation that I provided with the modified Color Forth.  I provided a Memory Map for your reference.  In the Memory Map, you will see there is about 5K of dictionary space from $43A0 to $5800.  The 8 screen buffers (8K) sit between $2380 and $43A0, and the Return Stack and TIB are under that at $2280 to $2380 Finally, the Data Stack and the User Variables lie between $20AA and $2280.
>
> It’s all a tight squeeze to get it all in the lower 32K along with the CoCo DECB system.
>
> I fear that you are using up all of something there in memory when you do that giant ALLOT, but since I’m not a Forth architect, I cannot say what.  Hopefully, the Memory Map will help you to determine the limits of what you are trying to do.
>
> If I could get a solid remote terminal facility working, I could free up the 8K currently used by the 8 screen buffers, and Forth source code could be loaded from the remote terminal.  That could make for a much more comfortable programming environment, for sure.
>
> Good luck!
>
> smp
> - - -
> Stephen Pereira
> Bedford, NH  03110
> KB1SXE
>
>
> > On Mar 28, 2019, at 3:28 PM, M. David Johnson <mdj at bds-soft.com> wrote:
> >
> > Stephen -
> >
> >
> >
> > I did get successful runs of what I was attempting in ColorForth. (Please see question at the end of this email).
> >
> >
> >
> > But, along the way, I apparently ran into a Dictionary limit somewhere above address 22052 ($5624) and probably before address 22775 ($58F7).
> >
> >
> >
> > What I did (In Vcc):
> >
> >
> >
> > LSCR CCF-MISC OK
> >
> > 4 3 2 1 LOAD LOAD LOAD LOAD OK
> >
> > HERE . 18399 OK
> >
> > 0 VARIABLE AHERE 4364 ALLOT OK
> >
> >
> >
> > Although OK was returned, the system was also frozen at this point. I retried it three times with the same results.
> >
> >
> >
> > So, I restarted Vcc, did NOT load CCF-MISC, and proceeded as follows:
> >
> >
> >
> > HERE . 17312 OK
> >
> > 0 VARIABLE AHERE 4364 ALLOT OK
> >
> > HERE . 21688 OK
> >
> >
> >
> > At that point, I manually entered 2DUP, WHILE, AGAIN, REPEAT, and +LOOP from CCF-MISC; followed by the rest of my program, at which point:
> >
> >
> >
> > HERE . 22052 OK
> >
> >
> >
> > and the program ran properly.
> >
> >
> >
> > Note:    21688 – 17312 = 4376.
> >
> > 18399 + 4376 = 22775.
> >
> >
> >
> > Are you aware of an upper address limit on the ColorForth Dictionary space and, if so, what is that limit?
> >
> >
> >
> > --
> >
> > M. David Johnson
> >
> > <mailto:mdj at bds-soft.com> mdj at bds-soft.com
> >
>
>
> --
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-- 
Joel Rees

http://reiisi.blogspot.jp/p/novels-i-am-writing.html