AxPPA: Approximate Parallel Prefix Subtractor

Parallel prefix Subtractor is the most flexible and widely used for binary addition/subtraction. Parallel Prefix Subtractor is best suited for VLSI implementation. No any special parallel prefix Subtractor structures have been proposed over the past years intended to optimize area. This paper presents a new approach to new design the basic operators used in parallel prefix architectures which subtract the unit by using modified technique of 2’s complement. Verification will also be done using LFSR technique so we don’t need to apply any manually input to perform the subtraction process. We can analysis and create the difference in terms of area between parallel prefix Subtractor and BIST architecture of parallel prefix Subtractor. The number of multiplexers contained in each Slice of an FPGA is considered here for the redesign of the basic operators used in parallel prefix tree. The experimental results indicate that the new approach of basic operators make some of the parallel Prefix Subtractor architectures faster and area efficient.