HLO projects - TI-99 40 column text game using T40XB

RSS Bot · April 20, 2019

I have been going through my Atari 8-bit games and looking to translate them into TI-99 games, mostly BASIC. The games I wrote in Atari MSBASIC are fairly straight forward translations. Atari BASIC has the issue of strings being completely different but can be got around.
One thing that both Atari BASICs have in common is the Atari uses 40 column text. This can be a tedious issue to fix when translating to TI99 32 column text. You have to go through each line check, recheck, reformat recheck again etc...
It would be nice if the TI99 had a 40 column text mode... oh wait, it does it's just not easily accessible in XB. But some nice people, much smarter then I in all thing TI99, have addressed this deficiency. Enter the 'Senior Falcon' (Harry Wilhelm) with a wonderful little utility called T40XB which makes the 40 column mode usable from XB.
For more on it read this thread: http://atariage.com/forums/topic/289953-40-column-routine-or-early-version-of-xb24-for-xb/
Simply you use CALL LINK routines to call the T40 and use the 40 column routines in it's own screen.
Here is the file:
the ZIP file has a very nice booklet with it.

Now to the game.
To test this 40 column routine I chose the simple game 'Civil War'. It's from David Ahl 'BASIC computer games book'. Here's a copy of the book online:
https://www.atariarchives.org/basicgames/

How I got this game from the Atari to the TI99 was thus:
1.) load the game in Atari Altirra emulator.
2.) print the game to text.
3.) do global REM of lines that the TI99 won't understand (such as POP)
4.) global replace PRINT with CALL PR(..
5.) create CALL routine:
CALL PR(A$)
CALL LINK ("PRINT",25,1,A$)
SUBCALL
6.) Now go through the program and change other things such as INPUT and replace multiple PRINTs with SCROLL
7.) start classic99 and paste in the code and save, test, save, test .....

All in all this conversion didn't take that long since string use was minimal and I didn't have to go line by line reformatting.

The T40XB does eat into the stack area in the VDP so you will have about 2k less memory for created CALLS and string arrays. It doesn't use any main memory though.
It does, currently, have an issue with classic99 sometimes locking up the emulator but Tursi is looking into that.
Here is the game disk:
from the menu press 2. It starts the T40XB package which calls the civil war game.
be sure to check out the manual booklet.
chow for now, HLO