Comments on “Self-Checking Carry-Select Adder Design Based on Two-Rail Encoding” [Dec 07 2696-2705]

We first show that self-checking presented in the above paper (ibid., vol. 54, no. 12, pp. 2696-2705, Dec. 2007) does not work for carry-select adder with input bits higher than 2. Then, we present a correct design and show that the resulting overhead almost doubles.