Systems for using shifter circuit and 3×3 convolver units to emulate functionality of larger sized convolver units

Abstract

Convolution with a 5×5 kernel involves computing the dot product of a 5×5 data block with a 5×5 kernel. Instead of computing this dot product as a single sum of 25 products, the dot product is computed as a sum of four partial sums, where each partial sum is computed as a dot product of a 3×3 data block with a 3×3 kernel. The four partial sums may be computed by a single 3×3 convolver unit over four time periods. During each time period, at least some of the weights received by the 3×3 convolver unit may correspond to a quadrant of weights from the 5×5 kernel. A shifter circuit provides shifted columns (left or right shifted) of the input data to the 3×3 convolver unit, allowing the 3×3 convolver unit access to the 3×3 data block that spatially corresponds to a particular quadrant of weights from the 5×5 kernel.