1. A method of encapsulating a long instruction in a set of short instructions for execution on a processor, the long instruction having k bits and each short instruction having l bits where l>k, the method comprising: assembling in a memory accessible by said processor a first portion of the long instruction and a first identifier to form a first instruction of the set of short instructions; and assembling in a memory accessible by said processor a second portion of the long instruction, a second identifier and a format identifier to form a second instruction of the set of short instructions; wherein at least one of the first and second identifiers is for identifying to the processor that the set of short instructions encapsulates the long instruction and wherein the format identifier identifies to the processor a predefined conversion method for assembling the long instruction from the set of short instructions.