8th July 2012
It took me a few hours just for me to try and figure out how I could get the upward scrolling correct for the front end. I came up with a few experiments, which sadly didn't work. Then I tried changing the AND value to #$06. The upscroll moved upwards smoothly. I created a fake multiplexor for the sprite scroll and also to mask the top part of the upward scrolling message - which thankfully did the trick nicely. A couple of things I need to add to the front end, are routines to change interrupts and display the help screen for a short period of time. Then back to the up scroll interrupts again. There's also the high score name entry to work on (carefully) as well.