Re: [stella] keypad example

[Darrell Spice <dspice@xxxxxxxxxxxxxx>]

On Apr 16, 2004, at 8:11 PM, Stephen Anthony wrote:

> On April 16, 2004 10:23 pm, Darrell Spice wrote:
> > I've got reading the keypad figured out, but am having a problem with
> > the joystick not registering the direction left. All other directions
> > & fire button work fine.   Anybody have any ideas?
>
> This isn't working in either Stella or z26 for Linux.  But I don't know
> what the problem could be ...
>
> Steve

thanx for taking a look.  I found it this morning, amazing what a bit 
of sleep can do :-)

the problem was the color value was in the high-nybble of X.  Because 
the lower nibble had all 0's, DEX decreased the high-nybble by one, but 
INX increased the low-nybble by one w/out affecting the high-nybble.

To fix the problem, I LSRed 4 times before putting the color into X, 
then ASLed 4 times after transferring the color back to A.

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Darrell Spice, Jr.
http://www.spiceware.org/