When using the MirageOS user installable interrupt in a program, do you need to do a RET or a RETI after the interrupt??? What's the difference? (I know it has something to do with some Z80 built-in flip-flop-switches, but...) And do you need to exx \ ex hl,hl'? Do you need to preserve any register when using the MiragOS user interrupt? Henk Poley