[Coco] Extended basic 1.1 command?

[Harry Hurst]

> Oops, I get it now:  bit 7 is the joystick comparator bit and must be
> forced to one;  bits 2-6 should already be ones if no keys are down.
> Right?
>

Bits 2-7 don't matter in this case. They all have to be forced to either 0
(AND 3) or 1 (OR &HFC) before you can determine the values on the button
bits, 0 and 1. To do otherwise leaves too many possibilities open, and
invites, if not disaster then at least a headache. If you wanted to also
check some of the other bits you could PIA0= PEEK(&HFF00) and then BUT=
PIA0 AND 3. Then the other bits are still there in PIA0 when you are done
processing the buttons.

HH