Simultaneous Floating-Point Sine and Cosine for VLIW Integer Processors

Graphics and signal processing applications often require that sines and cosines be evaluated at a same floating-point argument, and in such cases a very fast computation of the pair of values is desirable. This paper studies how 32-bit VLIW integer architectures can be exploited in order to perform this task accurately for IEEE single precision (including subnormals). We describe software implementations for sinf, cosf, and sincosf over [-pi/4, pi/4]that have a proven 1-ulp accuracy and whose latency on STMicroelectronics' ST231 VLIW integer processor is 19, 18, and 19 cycles, respectively. Such performances are obtained by introducing a novel algorithm for simultaneous sine and cosine that combines univariate and bivariate polynomial evaluation schemes.