Ford COMPUTRUCK

[rprosperi]

(11-01-2022 05:16 PM)Jeff_Birt Wrote:  

(11-01-2022 04:39 PM)Bill (Smithville NJ) Wrote:  I would be interested in seeing the HVAC software that you dumped from the ROM module. I've worked in HVAC engineering and would be curious to see what programs it had.

73
Bill WD9EQD
Smithville, NJ

I will upload it to Git hub soon. One ROM is called 'LOGIC jr II' and has 4 16K banks. The code is classic BASIC spaghetti. The second is on a Pygmy Software PCB, no bank switching, and the EPROM may be corrupt or failing. There is a block of data before the BASIC program starts that I'm trying to figure out.

Application code for these machines was developed on PCs using a 'compiler' (actually a tokenizer) and those tools also optimized the code for various reasons, though mostly for size (reduce byte count to get more code into the EPROM) and in fewer cases for speed. The resulting code, when un-tokenized back into BASIC, often looked highly spaghettified and fairly ugly, this is probably the reason.

It turns out some very un-obvious commands and sequences are much smaller than the 'normal' intuitive commands.

As an analogous HP-75 example of these unintuitive commands, consider this line:

Code:

50 C$=CAT$ @ IF NOT DELAY? OR C$[COS(EPS),6]="AUTOST" THEN 110

"COS(EPS) is used instead of "1" because the program is a few bytes shorter. So these kinds of of substitutions were made by the 'compiler' to save space, but when looking at the equivalent BASIC source code, it looks like something is broken.