Comparison of branching CORDIC implementations

Abstract

We compare implementations of Duprat and Muller's branching CORDIC and Phatak's double step branching (DSB)-CORDIC algorithms for sine and cosine evaluation. For reference we also report on classical CORDIC implementations for the same wordlengths. We have also implemented double stepping in the classical algorithm and report on the performance of this method. CORDIC evaluation of sine and cosine includes two parts, the zeroer and the rotator. We discuss implementation issues related to the minimization of the delay of each iteration of the algorithm (including delays for both the zeroer as well the rotator). We then examine hybrid methods that select the components from different algorithms (such as a DSB zeroer together with a classical rotator or vice versa).