A New High-speed and Low Area Efficient Pipelined 128-bit Adder Based on Modified Carry Look-ahead Merging with Han-Carlson Tree Method

S. Ghafari, M. Mousazadeh, A. Khoei (Urmia Univ., Iran), A. Dadashi (Univ. Oslo, Norway)

In this paper, a 128-bit pipeline Adder is presented, in the form of a syntactic Tree Adder by an introduction of a new modified Carry-Look-Ahead ( CLA) that is merged inside the Tree adder. The difference between proposed modified Carry-Look-Ahead and conventional Carry-Look-Ahead is that by increase in the number of Carry-Look-Ahead single-block input reduces the number of groups, subsequently raises the performance of conventional Carry-Look-Ahead. In order to add two 128-bit numbers, this modified Carry-Look-Ahead are merged with Tree algorithm, that the results of it have a significant improvement in complexity and gates count (25%), compared to the existing methods. This makes a significant reduction in transistor count and area efficiently.