@loop:
subleq @tmp, @IN
subleq @tmp, @IN
subleq @OUT, @tmp
subleq @tmp, @tmp, @loop

YOU NEED TO TRY LIKE THIS

@one: .data 0

@two: .data @IN

@three: .data 3

@four: .data 0

@five: .data @IN

@six: .data 6

@seven: .data @OUT

@eight: .data 0

@nine: .data 9

@ten: .data 0

@eleven: .data 0

@twelve: .data 0