Given
integer A = 8'shA5;
integer B = 8'shB6;
integer C = 8'hA5;
integer D = 8'hB6;
reg signed [31:0] S;

Evaluate
i.  S = A + B;
ii. S = A + B + 0;
iii. S = C + D;
iv. S = C + D + 0;
v. S = A + D;
vi. S = A + D + 0;