Reducing the Computation Time in (Short Bit-Width) Two's Complement Multipliers

Two's complement multipliers are important for a wide range of applications. In this paper, we present a technique to reduce by one row the maximum height of the partial product array generated by a radix-4 Modified Booth Encoded multiplier, without any increase in the delay of the partial product generation stage. This reduction may allow for a faster compression of the partial product array and regular layouts. This technique is of particular interest in all multiplier designs, but especially in short bit-width two's complement multipliers for high-performance embedded cores. The proposed method is general and can be extended to higher radix encodings, as well as to any size square and m \times n rectangular multipliers. We evaluated the proposed approach by comparison with some other possible solutions; the results based on a rough theoretical analysis and on logic synthesis showed its efficiency in terms of both area and delay.