4.3. Half and Full Subtractor

Try these first

1. 1.

   What is the difference when subtracting 0 from 1 using a half subtractor?

   Hint

   Think about 1 - 0.

2. 2.

   What are the outputs of a half subtractor when the inputs are A=1 and B=1?

   Hint

   Consider A and B being equal.

3. 3.

   What is the difference produced by a half subtractor with inputs A=1, B=0?

   • 0
   • 1
   • Borrow

   Hint

   Consider the basic subtraction logic.

4. 4.

   True or False: A full subtractor can provide a borrow output.

   • True
   • False

   Hint

   Think about additional input states.

5. 5.

   Given binary inputs A=1, B=1, and B_in=1, determine the outputs of a full subtractor.

   Hint

   Calculate the difference while considering the borrow input.

6. 6.

   Explain the design and functionality of a circuit that uses both half and full subtractors to process multi-bit subtraction.

   Hint

   Think about how you would connect them in a sequence.