Function approximation on decimal operands

CORDIC is a well-known method to approximate mathematical functions. It basically works as an iterative algorithm for approximating rotation of a two-dimensional vector using only shift and add operations. The method has been widely applied in the design of digital signal processors and in the computation of typical signal processing functions. It was specifically developed to process data expressed in radix-2. On the other hand, decimal computation has been gaining renewed interest over the last few years, and high performance decimal computation systems are being required on different scopes. In this paper, an improved CORDIC-based method so as to approximate functions on decimal operands is proposed. The algorithm will work with BCD operands, so no conversion to/from radix-2 is needed. An important reduction in the number of iterations in comparison to other CORDIC methods is achieved. The new algorithm is implemented on an FPGA so as to obtain results on delay and hardware resources. The experiments showing the advantages of the new method, with regard to both delay and precision, are described.