Method for performing complex fast fourier transforms (FFT's)

摘要

A method in a computer system of performing a butterfly stage of a complex fast fourier transform of two input signals. First, a packed multiply add is performed on a first packed complex value generated from a first input signal and a set of trigonometric values to generate a first product. Then, a second product is generated which comprises the first product with a sign inverted. A packed add of the second product and a second complex value generated from a second input signal is performed to generate a first result, and the first product and the second complex value to generate a second result.