An Introduction to Programming C-64 Demos
I found this wonderful introduction to programming C-64 demos. Ah, those were the days
* = $0801
lda #$00
tax
tay
jsr $1000 ; initialize musicmainloop: lda $d012 ; load $d012
cmp #$80 ; is it equal to #$80?
bne mainloop ; if not, keep checkinginc $d020 ; inc border colour
jsr $1003 ; jump to music play routine
dec $d020 ; dec border colour
jmp mainloop ; keep looping