VHDL code SUM < = A XOR B Carry < = A AND B where A and B are inputs, represents

VHDL code SUM < = A XOR B Carry < = A AND B where A and B are inputs, represents Correct Answer Half adder

Clearly this is the code of a Half adder where:

• the Sum bit is the XOR of the two input bits
• the carry bit is simply the AND of the two input bits

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A half adder circuit is basically made up of an AND gate and an XOR gate as shown below:

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• A half adder is also known as XOR gate because XOR is applied to both inputs to produce the sum
• Half adder can add only two bits (A and B) and has nothing to do with the carry
• If the input to a half adder has a carry, then it will neglect it and adds only the A and B bits
• That means the binary addition process is not complete and that's why it is called a half adder

Sum (S) = A⊕B, Carry = A.B