MadeEasy Test Series: Digital Logic - Number Representation

Question

Consider the addition of the two numbers 10001110 and 10000000 in an 8-bit ALU. Which of the following best summarizes the result and the status of the Z(zero), S(sign), C(carry) and O(overflow) flags? Assume that the numbers are represented in 2's Complement format and that S=1 if the result is negative.

a) Sum = 100001110, Z = 0, C = 1, O = 0, S = 1

b) Sum = 00001110, Z = 0, C = 0, O = 1, S = 0

c) Sum = 100001110, Z = 0, C = 0, O =1, S = 0

d) Sum = 100001110, Z = 0, C = 1, O =1, S = 0

Comments

D is ans

Answer 1

A           10001110
B           10000000
SUM :  100001110

Z = 0     C = 1    S = 0

Comments

Overflow bit also be 1

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when we adding two negative numbers in 2's complement how can result be a positive bcoz in solution sign bit is set to 0