I need a help on several points in my design, well the design is like this :

1.(input two numbers) *2

2.
if c = 0 ---> input1 + input2
if c = 1 ---> input1 - input2

3. output the bigger number of the two inputs.

please someone help me because this subject is really hard for me and i'll lose my scholarship if I get low grades on this subject! if you don't want to do the whole design just tell me what should I do I'll lookup the steps, thanks!

 

I am missing the design part.

 

I am missing the design part.

that's the problem I don't know how to start it...

 

You can start with better description of the assignment.

 

What kind of circuit are you supposed to be designing? Where do these inputs come from? How is the output handled? What is this parameter 'c' and where does it come from?

 

You can start with better description of the assignment.

What kind of circuit are you supposed to be designing? Where do these inputs come from? How is the output handled? What is this parameter 'c' and where does it come from?

I'm using a software called logisim, You input two numbers (A1A0, B1B0) using pins, and another pin called C , if C = 0 then its A1A0 + B1B0, if C= 1 then its A1A0 - B1B0, and then when we get the result we multiply it by two, and the circuit should also determine the bigger number (A1A0 OR B1B0).

I'm guessing adders and subtractors and comarators, yet I don't know what else to use OR how to effeciently use them.

I hope I was able to answer your questions .

 

So how could you use a 2-bit full adder to implement subtraction in response to a control signal?

If you have a subtractor, how can you determine which of two numbers is bigger?

 

So how could you use a 2-bit full adder to implement subtraction in response to a control signal?

If you have a subtractor, how can you determine which of two numbers is bigger?

I cant answer the first one but the 2nd I'd say before we do the arithmatic operation we compare

 

I cant answer the first one but the 2nd I'd say before we do the arithmatic operation we compare

So how do you do the compare?

If I have two numbers, A and B, there is an arithmetic operation that I can perform that will trivially allow me to state, based on the result of that operation, whether A>B, A<B, or A=B. What operation is that?

 

So how do you do the compare?

If I have two numbers, A and B, there is an arithmetic operation that I can perform that will trivially allow me to state, based on the result of that operation, whether A>B, A<B, or A=B. What operation is that?

using the comparator?

 

A comparator is not an arithmetic operation. Think addition, subtraction, multiplication, and division.