A processor system comprises a plurality of dot product processor units and element-wise multiplication units. The dot product processor units perform a depthwise convolution of a data matrix with a separate depthwise convolution weight matrix for each data matrix channel. Each dot product processor unit performs at least a portion of the depthwise convolution for one or more data matrix channels. The element-wise multiplication units perform multiplication operations of a pointwise convolution. Each element-wise multiplication unit applies to each depthwise convolution partial result element received from one or more of the dot product processor units a corresponding data element from each of a plurality of pointwise convolution weight filters to determine element-wise multiplication unit results. The processor system sums together different groups of data elements from the element-wise multiplication unit results to at least in part calculate different data elements of a result of the pointwise convolution.