Re: [stella] Newbie: Efficiency in Code, Joystick Routine as Example

[Glenn Saunders <cybpunks2@xxxxxxxxxxxxx>]

At 11:56 AM 7/14/2002 -0700, you wrote:
> This looks bizarre, don't it?
> Here's how it works:
> First we need to know how the values returned by SWCHA look in binary.
>     $EF = 1110 1111    ;up
>     $DF = 1101 1111    ;down
>     $BF = 1011 1111    ;left
>     $7F = 0111 1111    ;right


This would only work for 4-direction type games (ala Pac Man, Frogger, etc..)
Remember that the joystick supports 8 positions so for the diagonals two of 
the bits flip to zero, not just one.

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