Methods and apparatus for efficient complex long multiplication and covariance matrix implementation

A digital signal processor for computing various types of complex multiplication is described. The digital signal processor operates in conjunction with registers, a multiplier, an adder, and a multiplexer The Registers store first and second complex operands. The multiplier simultaneously performs multiplications to produce each combination of products between the real and imaginary terms of the first and second complex operands. The multiplexer selects which produced products are added to or subtracted from each other based on the type of complex multiplication being performed. The adder simultaneously performs additions and subtractions, if necessary, to produce both real and imaginary results depending on whether the type of complex multiplication being performed is a conjugated operation. The registers store the results of the complex multiplication.