In this paper we present a novel adder/subtracter arithmetic unit that combines Binary and Binary Code Decimal (BCD) operations. The proposed unit uses effective addition/subtraction operations on unsigned, sign-magnitude, and various complement representations. Our design overcomes the limitations of previously reported approaches that produce some of the results in complement representation when operating on sign-magnitude numbers. The proposal can be implemented in ASIC as a run time configurable unit as well as in reconfigurable technology in form of a run-time reconfigurable engine. When reconfigurable technology is considered, a preliminary estimation indicates that 40% of the hardware resources are shared by the different operations. This makes the proposed unit highly suitable for reconfigurable platforms with partial reconfiguration support. The proposed design together with some classical adder organizations were compared after synthesis targeting 4vfx60ff672-12 Xilinx Virtex 4 FPGA. Our design achieves a throughput of 82.6 MOPS with almost equivalent area-time product when compared to the other proposals.
展开▼
