Input Device Determination

[Jeff-20]

In programming a multi-load game, is there a way to determine if the game was loaded from tape or disk (or whatever device number) without prompting the user? The goal is to load the subsequent part with the right device number.

[IsaacKuo]

You could assume the screen looks something like this:

Code: Select all

...
LOAD"FLEAS.PRG",8

SEARCHING FOR FLEAS.PR
G
LOADING
READY.
RUN

Based on this assumption, you PEEK the screen for the LOAD command, and parse out the device number (if any).

[Jeff-20]

There must be a PEEK for the last input device employed. Perhaps I should ask the greater question: Do we have the patience for multi-load games outside of disk format? How many of you have the patience to play something that loads in parts from tape?

[Alan]

If I understand you, I think PEEK(186) is what you're looking for.

[Mike]

And autostarting the next part is a one-liner:

Code: Select all

PRINT"{CLR}LOAD"CHR$(34)"<name>"CHR$(34)","PEEK(186):POKE631,19:POKE632,131:POKE198,2:END

[IsaacKuo]

I don't understand what POKE632,131 does. Looking up my VIC20 Programmers Reference Guide, I gather that you're putting two characters into the keyboard buffer, but I don't know what CHR$(131) does. I would have guessed you'd need to put in a bunch more keys, like "{home}{return}run{return}" (that's stuffing 6 keys into the keyboard buffer).

[Mike]

The value 131 within the keyboard buffer is interpreted as if SHIFT+{STOP} (i.e. {RUN}) had been entered.

This is expanded to LOAD+{RETURN} (which overwrites the begin of the first line, but obviously does no harm), and RUN+{RETURN}.

[carlsson]

We're eternally thankful that SHIFT+RUN/STOP doesn't yield LOAD: just like many fastloader cartridges have a function key assignment to RUN: plus Return key.

[nbla000]

And autostarting the next part is a one-liner:

Code: Select all

PRINT"{CLR}LOAD"CHR$(34)"<name>"CHR$(34)","PEEK(186):POKE631,19:POKE632,131:POKE198,2:END

I've used this technique for almost all re-typed PaperSoft games to allow them to work for both tape or disk.