hello.z80

    .org    0000h
loop:
        ld      b,00h
        ld      d,01h
fibo:
        ld      a,b
        out     (0FFh),a
        add     a,d
        ld      b,d
        ld      d,a
        cp      79h
        jr      z,loop
        jr      fibo

    .end