The following task is from an old exam and because the new exam will be similar to this one, I'm trying to understand it. Unfortunately there are no solutions or hints given and I got nothing to understand it really (I can provide source that this is really from an old exam and NOT homework.)
Given is a comparator that compares
4-bit binary numbers
A_3, A_2, A_1, A_0 ..). The result is the output signal
C_i which has the value
A > B.
The arithmetic-circuit is supposed to be made up by connecting
1-bit arithmetic-modules. Each of these
1-bit modules have the inputs
A_i, B_i and
C_i-1 and the output
i= 0, 1, 2, 3. So, the carry outputs will be taken of the less significant digit
B=0010. Fill the following table whereby
C_-1-bit is supposed to be chosen by you in a reasonable way. The carry
1 exactly when
A > B
I have filled the table as good as I could but I have no idea how to do it with
C_i-1. The fields I have filled, are they correct at all?
I also hope I have explained clear enough please do tell me if I did not. You guys are really my last chance, got no one and nothing else to understand this I'm totally serious : /
**Edit: I would fill C(i-1) in table like that: 0 0 1 0 it's right now?