LOOP (128)
D[4,0] = +(S1[4,0], S2[4,0])
D[4,1] = +(S1[4,2], S2[4,2])
D[4,2] = +(S1[4,1], S2[4,1])
D[4,3] = +(S1[4,3], S2[4,3])
