CARRY-SKIP ADDER HAVING MERGED CARRY-SKIP CELLS WITH SUM CELLS

摘要

A multi-bit adder includes a carry chain, a carry-skip network, sum cells, anda carry-sum cell. The carry chain propagates, generates, or kills carry-in bits.The carry-skip network is coupled to the carry chain to selectively skip the carry-inbits over at least one portion of the carry chain. The sum cells are coupled alongthe carry chain to sum the carry-in bits with corresponding bits of two operandsto generate a multi-bit resultant. The carry-sum cell is coupled to receive oneof the carry-in bits to a single intermediate bit position on the carry chain andto generate one bit of the multi-bit resultant having a more significant bit positionthan the single intermediate bit position.