; 4, 4, 2
# all zero -- sum to zero (unsigned)
0,0,0
0,0,1
# overflow to zero
80000000,80000000,0
00000000,ffffffff,1
# overflow to nonzero
80000001,80000001,0
80000001,80000000,1
# signed overflow
40000000,40000000,0
40000000,40000000,1
-4000000,-40000001,0
-4000000,-40000002,1
ffffffff,80000000,0
ffffffff,80000000,1
