A program storage medium storing an emulation system for performing dynamic real time translation of first program code written for the first programmable machine into second program code (target code) for running on a second programmable machine employing run time generation of an intermediate representation of the first program code. Upon first encountering a given portion of program code, only the target code necessary to execute that portion of program code under a prevailing set of entry conditions is initially generated and stored. When the same portion of program code is again encountered, a determination is made as to whether intermediate representation corresponding to a second subsequent set of conditions has been generated. If not, the target code necessary to execute the same portion of program code under that second set of conditions is generated.