1. A method of execution control for use during program code conversion of a subject program into target code executable by a target processor, said method comprising the steps of: (a) providing a translator run loop which sets a subject block in the subject program as a current subject block; (b) calling a translator trampoline function from the translator run loop; (c) calling from the translator trampoline function either to a translator code generator function to generate and store a target code block from the current subject block, or else calling and executing a previously stored target code block corresponding to the current subject block; and (d) returning to the translator trampoline function and repeating the step (c) for another subject block, or else returning from the translator trampoline function to the translator run loop.