Reconfigurable multiply-accumulate hardware co-processor unit

摘要

A reconfigurable co-processor adapted for multiple multiply-accumulate operations includes plural pairs of multipliers, plural first adders receiving respective product outputs from a pairs of multipliers, and at least one second adder receiving sum outputs from a corresponding pair of first adders. The co-processor includes sign extend circuits at the output of each multiplier. One multiplier of each pair has a fixed left shift circuit that left shifts the product output a predetermined number of bits. The other multiplier in each pair includes a right shift circuit that right shifts the product output the number of bits. Multiplexers at the output of the first multiplier in each pair select the sign extended or the left shifted products. Multiplexers at the output of the second multiplier in each pair select the product, the right shifted product or pass through the inputs. The sign extend circuit for the second multiplier follows the multiplexer. Third adders receive the sum outputs of the second adders and produce a third sum output. These third adders include plural selectable output accumulators and variable right shifter at their outputs. The third adders may separately sum the product sums from four multipliers each. Alternatively, the third adders may accumulate the products of eight multipliers.