1. A method for utilizing bits in an illegal op code in order to not increase the number of bits required to represent each instruction comprising the steps of: fetching a plurality of instructions from a memory; re-encoding one or more illegal op codes of one or more instructions into a single illegal op code if said one or more instructions comprise illegal op codes that are a member of a group of illegal op codes; pre-decoding a fetched instruction that does not have an illegal op code; and re-encoding one or more fields of said pre-decoded instruction into a previously illegal op code which was re-mapped into said single illegal op code.