A proposed high performance gigaflop signal processor is described in which 512 processors are interconnected with a 768 by 768 crossbar switch utilizing a spatial light modulator of the type presently under development at Texas Instruments. Optical fibers are used to provide high speed communication between the processors and the switch. The system, processor nodes, programming, and functional operation are described. The advantages are discussed for reconfigurability, optical crossbar switches, and programmed data flow. Efficient implementations are presented for a systolic filter, a fast Fourier transform, a correlator, and a matrix-vector multiplier. Preliminary performance estimates suggest that over one gigaflop performance is achievable for these algorithms on this processor.