Full adder implementations

Cout = A B + Cin (A xor B) = A B + B Cin + A Cin

• Standard approach

  • 6 gates
  • 2 XORs, 2 ANDs, 2 ORs

• Alternative implementation

  • 5 gates
  • half adder is an XOR gate and AND gate
  • 2 XORs, 2 ANDs, 1 OR

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