1. An apparatus for performing message passing decoding operations, the apparatus comprising: storage means for storing L sets of Z K-bit messages, where Z is a positive integer greater than one and K and L are non-zero positive integers; a node processor including a plurality of node processing units, each node processing unit for performing at least one of a constraint node processing operation and a variable node processing operation; and switching means coupled to the storage means and to the node processor, for passing sets of Z K-bit messages between said storage means and said node processor and for reordering the messages in at least one of said sets of messages in response to switch control information.