1. A microprogrammed parallel processor including a plurality of processing units, operable under control of microinstructions each containing a plurality of micro-operations, said microprogrammed parallel processor comprising: means for executing, during a cycle, each of said plurality of micro-operations, within a microinstruction, for which a required processing unit is available; means connected to said executing means for indicating which micro-operations were not executed during the cycle; means, connected to said executing means and said indicating means for recycling only those micro-operations within said microinstruction for which said indicating means indicated as not executed during the cycle, for execution by said executing means in a subsequent cycle as each required processing unit becomes available; and means, connected to said means for recycling, for storing said microinstruction until all of said plurality of micro-operations within said microinstruction are executed.