Implementation and comparison of effective area efficient architectures for CSLA

Abstract

In the design of Integrated circuit area occupancy plays a vital role because of increasing the necessity of portable systems. Carry Select Adder (CSLA) is a fast adder used in data-processing processors for performing fast arithmetic functions. From the structure of the CSLA, the scope is reducing the area of CSLA based on the efficient gate-level modification. In this paper 16 bit, 32 bit, 64 bit and 128 bit Regular Linear CSLA, Modified Linear CSLA, Regular Square-root CSLA (SQRT CSLA) and Modified SQRT CSLA architectures have been developed and compared. However, the Regular CSLA is still area-consuming due to the dual Ripple-Carry Adder (RCA) structure. For reducing area, the CSLA can be implemented by using a single RCA and an add-one circuit instead of using dual RCA. Comparing the Regular Linear CSLA with Regular SQRT CSLA, the Regular SQRT CSLA has reduced area as well as comparing the Modified Linear CSLA with Modified SQRT CSLA; the Modified SQRT CSLA has reduced area. The results and analysis show that the Modified Linear CSLA and Modified SQRT CSLA provide better outcomes than the Regular Linear CSLA and Regular SQRT CSLA respectively. This project was aimed for implementing high performance optimized FPGA architecture. Modelsim 10.0c is used for simulating the CSLA and synthesized using Xilinx PlanAhead13.4. Then the implementation is done in Virtex5 FPGA Kit.