Accurate function approximations by symmetric table lookup and addition

This paper presents a high-speed method for accurate function approximations. This method employs parallel table lookups followed by multi-operand addition. It takes advantage of leading zeros and symmetry in the table entries to reduce the table sizes. By increasing the number of tables and the number of operands in the multi-operand addition, the amount of memory is significantly reduced. This method provides a closed form solution for the table entries and can be applied to a variety of elementary functions. Compared to conventional table lookups, it requires two to three orders of magnitude less memory. The design of elementary function generators that use this method are presented and compared to similar methods for elementary function generation.