Register Usage: 
---------------
R0  based address of vector V
R1  number of elements to be processed
R2  the value of V[R0+R1]
R3  the sum of elements seen so far
R4  the constant 1 for subtraction

Memory Usage: 
-------------
1000: the length of V, say N
1001..1000+N: the elements of N

starting at 1: the program
       (ldi 0 1000)	 1
       (ld 1 0)		 2 
       (ldi 3 0)	 3
       (ldi 4 1)	 4
SumSq: (bez 1 END)	 5 
       (ldx 2 1 0)	 6
       (mul 2 2 2)	 7
       (add 3 3 2)	 8
       (sub 1 1 4)	 9
       (jmpi SumSq)	10
End:   (print 3)	11
       (newline)	12