Faithful single-precision floating-point tangent for FPGAs

This paper presents an FPGA-specific implementation of the floating-point tangent function. The implementation inputs values in the interval [-π/2,π/2], targets the IEEE-754 single-precision format and has an accuracy of 1 ulp. The proposed work is based on a combination of mathematical identities and properties of the tangent function in floating point. The architecture was designed having the {Stratix-IV} DSP and memory blocks in mind but should map well on any contemporary FPGA featuring embedded multiplier and memory blocks. It outperforms generic polynomial approximation targeting the same resource spectrum and provides better resources trade-offs than classical CORDIC-based implementations.The presented work is widely available as being part of the Altera DSP Builder Advanced Blockset.