1. A method of executing a threaded interpreter for interpreting a program comprising a series of program instructions, the method comprising for the execution of each program instruction: a plurality of preparatory steps making the program instruction available in the threaded interpreter, and an execution step emulating the program instruction, characterized in that during the execution of the interpreter on an instruction-level parallel processor machine instructions implementing a first one of the preparatory steps are executed in parallel with machine instructions implementing a second one of the preparatory steps for respective ones of the series of program instructions.