You can chain handlers by simply rewriting the interrupt vector. Something like this (for a sequence of two handlers): handler1 ; ... lda #

You can chain handlers by simply rewriting the interrupt vector. Something like this (for a sequence of two handlers): handler1 ; ... lda #<handler2 sta $fffe lda #>handler2 sta $ffff lda #line2 sta $d012 rti handler2 ; ... lda #<handler1 sta $fffe lda #>handler1 sta $ffff lda #line1 sta $d012 rti To my intuition it seems it would be quicker, though slightly larger. I've only skimmed through the article so maybe there's a reason the author considered this and opted not to. Running out of memory maybe?