'How to traverse memory for the Fibonacci sequence in ARM assembly

I must write the following function in its own assembly file: void fillFibonacciArray(int *array, int n); The function writes into the array the first n Fibonacci numbers, i.e., each element is the sum of the prior two elements.

What I have so far:

fillFibonacciArray:
        cmp r1, 0
        beq allDone

        mov r6, 1
        str r6, [r0]            @ Arr[0] = 1
        cmp r1, 1
        beq allDone

        mov r6, 1
        str r6, [r0, 4]         @ Arr[1] = 1
        cmp r1, 2
        beq allDone
        mov r4, 3               @ int i = 3


loop:
        ldr r2, [r0, -4]        @ Arr[i-2]
        add r5, r2, r0      @ Arr[i-2] + Arr[i-1]
        mov r6, r5              
        str r6, [r0, 4]         @ Arr[i] = Arr[i-2] + Arr[i-1]

        add r4, r4, 1           @ i++
        cmp r4, r1              @ i < n?? branch to loop if it is
        blt loop

        b allDone

allDone:
       bx lr

My confusion begins with accessing the previous two values. Do I use logical shifting to move around the array or is offsetting capable of accomplish this task? Any help is appreciated!

arraysassemblyarmfibonacci


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