.setcpu "65C02"

                ACIA_DATA       = $0000
                ACIA_STATUS     = $0001
                ACIA_COMMAND    = $0002
                ACIA_CONTROL    = $0003

                .segment "VECTORS"

                .word nmi
                .word reset
                .word irq

                .code

reset:          jmp main
nmi:            rti
irq:            rti

main:
init_acia:      lda #%00001011
                sta ACIA_COMMAND
                lda #%00011111
                sta ACIA_CONTROL

                ldx #33
loop:
wait_txd_empty: lda ACIA_STATUS
                and #$10
                beq wait_txd_empty
                txa
                sta ACIA_DATA
                inc
                cmp #127
                beq reset_counter
                tax

                ldy #$FF
:               cpy #0
                beq :+
                nop
                dey
                jmp :-
:

                jmp loop
reset_counter:  ldx #33
                jmp loop