Method and apparatus for generating boundary markers for an instruction stream including variable-length instructions

A method of generating boundary markers, for an instruction stream including variable-length instructions, includes generating a number of sets of potential boundary markers for a predetermined set of bytes within the instruction stream. Each set of potential boundary markers is generated based on a respective assumption regarding a boundary byte position within the predetermined set of bytes. For example, a number of sets of potential boundary markers may be generated based on assumptions that respective byte positions within the predetermined set of bytes include the start byte of an instruction. A further set of potential boundary markers may be generated based on an assumption that none of the byte positions within the predetermined set of bytes includes a start byte of instruction. A set of boundary markers, from the number of sets of potential boundary markers, is selected as a valid set of boundary markers when it is determined that an assumption, upon which the relevant set was generated, is in fact valid.