controller_strobe:
@controller1:
    lda #$01
    sta $4016
    lda #$00
    sta $4016
    lda control_pad1
    sta control_old1
    ldx #$08
:   lda $4016
    lsr A
    ror control_pad1
    dex
    bne :-

    lda control_pad3
    sta control_old3
    ldx #$08
:   lda $4016
    lsr A
    ror control_pad3
    dex
    bne :-

    ldx #$08
:   lda $4016
    lsr A
    ror
    dex
    bne :-
    cmp #$10
    bne @controller1
@controller2:
    lda control_pad2
    sta control_old2
    ldx #$08
:   lda $4017
    lsr A
    ror control_pad2
    dex
    bne :-

    lda control_pad4
    sta control_old4
    ldx #$08
:   lda $4017
    lsr A
    ror control_pad4
    dex
    bne :-

    ldx #$08
:   lda $4017
    lsr A
    ror
    dex
    bne :-
    cmp #$10
    bne @controller2
    rts