I created a single machine language .CO file
<https://github.com/hackerb9/crc16-modelt/blob/idtest/CRC16.CO> which
should run on any of the Model T variants (at least it does in emulation),
but now I’m trying to figure out how it would be loaded onto them. As a
binary it is not easy to transmit.
Ideally, I’d have a BASIC loader that would POKE the program into memory,
but the problem with that is that my .CO file is already 1.5 kilobytes
long, so it barely fits into memory on an 8K machine. (Which, in itself
wonders me. Please see my calculation below and correct me if I’m
mistaken.) I believe a BASIC loader would expand the file size and simply
not fit.
So my first question is: Is there something like TEENY for all Model
T’s,even for the less common variants like the Olivetti M10, that can
receive binary files over the serial port?
My second question is: Am I confused about the 1.5K limit on cross-platform
.CO files? I’m fairly new to assembly language on these devices and have
made some guesses based on what I’ve been observing in the Virtual-T memory
viewer. Let me state my presumptions explicitly, so you all can help me
figure out where, or if, I’m going wrong.
1.
A single .CO program can run on the Kyocera Kyotronic 85 and its sister
computers: TRS-80 Model 100, Tandy 200, Tandy 102, Olivetti M10, NEC
PC-8201A, and NEC PC-8300.
2.
All the Kyotronic kin must store a .CO file *twice* in memory: Once in
the filesystem and a second copy in high memory when it is loaded through
LOADM, RUNM, or by selecting it from the MENU. [Side question: Does
distribution on cassette get around this limitation? Do all machines have
the same audio encoding format?]
3.
The area in high memory which the .CO file is copied to before it runs
must be reserved using the command CLEAR 256, *x*, where 256 is the
space reserved for strings, *x* is the lowest memory address the .CO
file can occupy, and the builtin variable *MAXRAM*-1 is the highest.
4.
I’m defining *MINRAM* as the lowest address which can be reserved using
CLEAR. The value of MINRAM is higher on machines with less memory.
5.
To run cross-platform, we’d need to know the largest MINRAM and smallest
MAXRAM across all the Kyocera kin. The Tandy 200 has a MAXRAM of 61104. The
8K Model 100 has a MINRAM of 58044 (with no files and setting string space
to 0).
6.
Thus, the largest cross-platform machine language file would be:
[image: \frac{(61104-58044)}{2} = 1530 \text{bytes}]
and the space from 59574 to 61103 should be reserved for the .CO file
using the command
CLEAR 0, 59574
What is the right way to load a larger file? Or is it not possible and I
need to solve my problem in a different way? (I’ve already had to compress
the data strings to get it to fit at all. I could do more, but the code
would be uglier and harder to extend in the future.)
Thanks all for any help or suggestions,
—b9
