Processor for processing an artificial neural network operation

Processor (10) for processing an artificial neural network operation, comprising: a crossbar (12) comprising a plurality of crossbar (12) array entities, each crossbar (12) array entity comprising at least one synapse node (20), the at least one synapse node (20) is configured to be operated in a first synapse mode (m1) having one or more stored first weights, and in a second synapse mode (m2) using one or more second weights and/or in a third synapse mode (m3) using one or more fixed (stored) third weights; wherein the first synapse mode (m1) and the second synapse mode (m2) and the third synapse mode (m3) differ from each other with respect to a storing of the one or more weights as the stored first weights or second weights or third weights.