Split decision

I've knocked up some 6502 source for the A8 display app. It has a couple of blank lines just before the picture (as well as the usual ~30) the first of which kicks off the displaylist interrupt. That enters, does a WSYNC then a few dozen NOPs which allows timing the start of the cycle counted line routine to a position I want it to start.

To begin with I've turned off PMG DMA so there's an extra few cycles on the line (most at the start) so there's plenty of room to do the 4 changes before the start of the visible screen. Then there's the positions across the screen to cope with. The problem with that is there are quite a few options on where those colour changes can take place. I think a simplest fixed approach will do to begin with and I'll see where it goes from there.

Now to change the code to a partial line version. That'll split the line into the same positions the splits happen and I'll have to come up with a couple of methods to decide which colour to change.


Pete