1. A multiprocessor data processing system comprising: a first processor with a first memory cloner; a second processor with a second memory cloner; a memory subsystem; means for interconnecting said first and second processors and said memory subsystem; and a plurality of token operations that are issued from a particular one of said first memory cloner and said second memory cloner prior to a data clone operation, wherein said token operations reserve a source address and a destination address for a data clone operation originating from the particular first or second memory cloner.