FIBNCI: MOV  C,  A  ; C will store the counter
        DCR  C      ; decrement, because we know f(1) already
        MVI  A,  1
        MVI  B,  0
LOOP:   MOV  D,  A
        ADD  B      ; A := A + B
        MOV  B,  D
        DCR  C
        JNZ  LOOP   ; jump if not zero
        RET         ; return from subroutine