;========
; Macros
;========

.macro left_to_right
    in  @0, PORTD
    clc
    ror @0
    brcc PC+2
    ldi @0, 0b10000000
    out PORTD, @0
.endmacro

.macro right_to_left
    in  @0, PORTD
    clc
    rol @0
    brcc PC+2
    ldi @0, 0b00000001
    out PORTD, @0
.endmacro