[Coco] using .bas files with disk images

Robert Gault robert.gault at att.net
Fri Dec 30 05:48:58 EST 2011


L. Curtis Boyle wrote:
> It has been a long time since I put those files up, but I believe they were straight exports of the tokenized programs from Jeff Vavasour's Coco emulator disk utility (if that helps).
>
> L. Curtis Boyle
> curtisboyle at sasktel.net

Unfortunately, it doesn't :( PORT.EXE doesn't do a better job than the MESS 
utilities.

About the best we can do is add the file to a .dsk image as previously described 
but run Coco2 or Coco2b emulation. The file will LIST but won't stop on errors. 
It can then be saved in ASCII format.

I wrote a patch for the Coco3 ROM that amongst other things prevents the hangup 
when LIST sees "bad" tokens. I've converted the FOOTBALL.BAS file to ASCII on 
both a Coco2 and Coco3 and the listings are almost identical and both wrong.

A typical line of common code is
24 LOAD(18,5),"Welcome to C-Hawk Ball !"
seen in both Coco2 and Coco3 listings.
The only thing that might make sense for this line would be.
24 HPRINT(18,5),"Welcome to C-Hawk Ball !"

It does appear to be for a Coco3 when you look at line 10 on a Coco2 and Coco3:
Coco2
10 ! 44014,75:!44015,78
Coco3
10 HBUFF 44014,75:HBUFF44015,78
But then why is line 24 wrong on both a Coco2 and Coco3?

With enough effort it might be possible to find a common shift in the tokens and 
restore the original code by hand. It looks like custom tokens were patched into 
the ROM, the program saved in token format, and a normal Coco ROM can't 
interpret the resulting file.
If we give the authors the benefit of the doubt, there may have been a binary 
file that needed to be LOADMed prior to using the .BAS program. That could 
enhance the number of commands and functions.






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