Hardware circuit and method for multiplying sets of inputs, and non-transitory machine-readable storage device

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a hardware circuit configured as a signed multiword multiplier. The circuit includes a processing circuit that receives inputs that each have a respective bit-width. The processing circuit can represent at least one input as a signed multiword input based on the first input having a bit-width that exceeds a fixed bit-width of the hardware circuit. The circuit includes signed multipliers that are each configured to multiply signed inputs. Each signed multiplier includes multiplication circuitry configured to: receive the signed multiword input; receive a signed second input; and generate a signed output in response to multiplying the signed multiword input with the signed second input.