1. A multiple parallel execution unit system for executing instructions comprising: means for fetching fixed width instructions from a memory, each of the fixed width instructions comprising a portion for fetching a template instruction and a portion for containing variable parameters relating to the template instruction; means for pre-decoding each of the fetched instructions in turn; means for determining whether each of the pre-decoded instructions includes a portion for fetching a locally stored template instruction from local storage means; means for fetching the locally stored template instruction; means for opening and decoding the fetched locally stored template instruction; and means for causing the decoded fetched locally stored template instruction to be executed using the variable parameters included in the fixed width instruction.