Addition of 1's Complement Numbers
? Same as 2's complement except that instead of discarding the last carry, it is added to the n-bit sum in the right-most position ("end-around" carry).
(a) & (b) same as 2's complement
(c) Pos + Neg numbers, Neg > Pos
(d) Pos + Neg numbers, Pos > Neg
+1 0001 (correct; no overflow)
(e) Negative no's. |sum| <= 2^(n-1)
-7 1000 (correct; no overflow)
(f) Negative no's. |sum| > 2^(n-1)
0100 (wrong answer; overflow)