Para-CORDIC: parallel CORDIC rotation algorithm

In this paper, the parallel COrdinate Rotation DIgital Computer (CORDIC) rotation algorithm in circular and hyperbolic coordinate is proposed. The most critical path of the conventional CORDIC rotation lies in the determination of rotation directions, which depends on the sign of the remaining angle after each iteration. Using the binary-to-bipolar recoding (BBR) and microrotation angle recoding techniques, the rotation directions can be predicted directly from the binary value of the initial input angle. The original sequential CORDIC rotations can be divided into two phases where the rotations in each phase can be executed in parallel. Our proposed architectures have a more regular and simpler prediction scheme compared to previous approaches. The critical path delay is reduced since the concurrently predicted rotations can be combined using multioperand carry-save addition structures.