;int sum(int len, int arr[]) {
sum:
	;r1 = len
	;r2 = arr
	;r3 = i
	;r0 = sum
	ldis r0, 0;
	;r4 arr data
loop:
	;load arr data
	ldw r4, r2;
	;sum += arr[i];
	add r0, r0, r4;
	subi r3, r3, 1;
	retze-;
	addi r1, r1, 4;
	branch+ loop;