processor 6502 org $fe00 init cli lda #$00 sta $06 lda #$4 sta $07 loop jsr getin cmp #$00 beq loop jsr chrout jmp loop irqhandler jsr scnkey jsr udtim rti scnkey lda $dc01 bne next rts next ldx $c6 cpx #$0a beq quit2 sta $0277,x inc $c6 quit2 rts chrout ldy #$00 sta ($06),y inc $06 bne quit1 inc $07 lda $07 cmp #$08 bne quit1 lda #$04 sta $07 quit1 rts getin ldx $c6 beq nochar dex stx $c6 lda $0277,x rts nochar lda #$00 rts udtim inc $a2 bne quit3 inc $a1 bne quit3 inc $a0 quit3 rts org $ff9f jmp scnkey org $ffd2 jmp chrout org $ffe4 jmp getin org $ffea jmp udtim org $fffc dc.w init dc.w irqhandler