The sun () outputs are provided for each bit and the resultant carry (C4) is obtained from the fourth bit. This adder features full internal look ahead across all four bits. This provides the system designer with partial look-ahead performance at the economy and reduced package count of a ripple-carry implementation. The adder logic, including the carry, is implemented in its true for meaning that the end-around carry can be accomplished without the need for logic or level inversion.