A method for parallel instruction execution in a computer is described. If the computer is executing in the single-instruction mode and the computer encounters a first type of instruction with a dual-instruction mode bit having a first value, then one more single instruction is executed before dual-instruction mode instruction execution begins. The first type of instruction is an instruction having a dual-instruction mode bit. The dual-instruction mode instruction execution occurs in parallel. If the computer is executing in the dual-instruction mode and the computer encounters the first type of instruction with the dual-instruction mode bit having a second value, wherein the second value is different from the first value, then one more dual instruction is executed before single-instruction mode instruction execution resumes.