fib:
;  WRITTEN IN C WITH X86-64 CLANG 3.3 AND DOWNGRADED TO 16-BIT X86
;  INPUT: DI = THE NUMBER YOU WISH TO CALC THE FIBONACCI NUMBER FOR.
;  OUTPUTS TO AX

        push    BP
        push    BX
        push    AX
        mov     BX, DI        ;COPY INPUT TO BX
        xor     AX, AX        ;MOV AX,0
        test    BX, BX        ;SET FLAGS ACCORDING TO BX
        je      LBB0_4        ;IF BX == 0 RETURN 0
        cmp     BX, 1         ;IF BX == 1 RETURN 1
        jne     LBB0_3
        mov     AX, 1         ;ELSE, SET AX = 1 AND RETURN
        jmp     LBB0_4
LBB0_3:
        lea     DI, WORD PTR [BX - 1]   ;DI = BX - 1
        call    fib        ;RETURN FIB(BX-1)
        mov     BP, AX        ;STORE THIS IN BP
        add     BX, -2
        mov     DI, BX
        call    fib        ;GET FIB(DI - 2)
        add     AX, BP             ;RETURN FIB(DI - 1) + FIB(DI - 2)
LBB0_4:

   add sp,2
        pop     BX
        pop     BP
        ret