Relay CPU Fibonacci

        jmp start

       .resb 1024
stack: .resb 1


.macro call 1
    push a
    push b
    push c
    push d
    jsr %1
.endmacro

.macro ret 0
    rts
    pop d
    pop c
    pop b
    pop a
.endmacro


fib:    ldi c #1
        xor a
        brz one
        ldi c #2
        xor a
        brz one

        ldi c #-1
        add a
        ldi c #-2
        add d

        mov a b
        call fib
        push a
        mov d b
        call fib
        mov a c
        pop b
        add a

        ret

one:    ldi a #1
        ret


start:  ldsp stack

        ldi b #8
        call fib
        hlt