Re: [stella] request for comments: RESCUE.BIN

Subject: Re: [stella] request for comments: RESCUE.BIN
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Fri, 26 Sep 1997 20:01:56 GMT
>Speaking of building a custom something-or-other, I will ask this question
>because I know very, very little about programming stella.  Is it possible
>to program a game which checks for joystick combinations that are not
>naturally possible, like pushing left and right at the same time?  If so,
>a custom keyboard/control panel thing could be made with one button or key
>up, up/left, up/right, up/down, up/button, up/left/rt, up/left/down,
>up/left/button, up/rt/down, up/rt/button, up/down/button, etc... How do
>you calculate the number of combinations?  It's 5!, right?  If so, in
>theory, a 120 button control panel device could be made for the 2600.
>There must be a reason why Atari didn't do this.  Please enlighten me.

Probably expense.. what else besides BASIC Programming could have used
anything beyond the 12-key touch pad?  Also, with your setup, you can't
press multiple keys at once.  The TIA does have separate inputs for each
joystick direction, plus both buttons.  BTW, the number of combinations
wouldn't be 5!, it'd be 2^5... minus one to signal "no button pressed".

I can't think of a way for a custom controller to do more than one button
while retaining all four joystick directions, independent of the button.
With an eight-way stick (four diagonals) and one button, there's eighteen
possble configurations of stick and button (joystick in each of nine
positions * two button position).  Adding a second button doubles that to
36 possible configurations, or more than the (2^5)-1 = 31 theoretical limit
of the port.  Of course, you could add the second joystick port, but two
buttons independent of an eight-way stick cannot be done in one port on the

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