In computer programming, a p-code machine, or portable code machine is a virtual machine designed to execute p-code (the assembly language of a hypothetical CPU). This term is applied both generically to all such machines (such as the Java Virtual Machine and MATLAB precompiled code), and to specific implementations, the most famous being the p-Machine of the Pascal-P system, particularly the UCSD Pascal implementation (among whose developers the "p" in "p-code" was construed to mean "pseudo" more often than "portable", "pseudo-code" thus meaning instructions for a pseudo-machine) .