SELF-SYNCHRONIZATION CARRY LOOK AHEAD ADDER AND ITS ADDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a self-synchronization carry look ahead adder and its adding method.;SOLUTION: This carry look ahead adder is provided with: a carry generation/propagation part for dividing an adding number and an added number into M blocks to calculate a carry propagation bit value and a carry consumption bit value; a block carry part for generating a block carry in each block; a bit carry part for calculating, in each block, a first bit-based carry and a second bit-based carry for the case having the block carry and for the case without having the block carry by a Manchester carry chain; a control circuit having an output without being controlled by any clock signals by using the block carry for generating block carry generation information; and an addition value selection part for selecting any of the bit-based carries corresponding to the block carry generation information and for adding the bit-based carry propagation bit value to the selected bit-based carry for each bit to output the final addition result.;COPYRIGHT: (C)2004,JPO&NCIPI