Hardware efficient algorithms for trigonometric functions

A new algorithm is presented which significantly reduces the minimum amount of logic required to calculate sine, cosine, and square root. It is derived from an old method for computing certain inverse functions which was once considered for use in software, but then abandoned because of efficiency concerns. However, when reversed and combined with a restoring square root algorithm, a unique new design emerges which performs trigonometric calculations without the use of pre-stored constants or any internal operation more complex than binary subtraction. The design has been implemented with common TTL MSI logic and is found to be reasonably fast, very accurate, and to require considerably less hardware than a comparable CORDIC algorithm