P-code

P-code

(language)

The intermediate language produced by the Pascal-P compiler. P-code is the assembly language for a hypothetical stack machine, the P-machine, said to imitate the instruction set of the Burroughs 6700.

The term was first used in the Wirth reference below. Byte articles on writing a Pascal Compiler in Northstar BASIC (ca Aug 1978) also used the term.

P-code was initially the intermediate code generated by the P2 compiler from ETH Zurich. P-code was later used as the intermediate language in the UCSD Pascal System, and in its two main derivatives, Apple Pascal and the UCSD P-system.

Variants: P2 P-code, P4 P-code, UCSD P-code, LASL P-code.

[Algorithms + Data Structures = Programs, N. Wirth, P-H 1976].

["A Comparison of PASCAL Intermediate Languages", P.A. Nelson, SIGPLAN Notices 14(8):208-213, Aug 1979].

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

intermediate language

A language that is generated from programming source code, but that cannot be directly executed by the CPU. Also called "bytecode," "p-code," "pseudocode" or "pseudo language," the intermediate language (IL) is platform independent. It can be run in any computer environment that has a runtime engine for the language.

In order to execute the intermediate language program, it must be interpreted a line at a time into machine language when it is run or compiled entirely into machine language just before it is run or compiled entirely ahead of time and run when required.

A Popular Architecture
Visual Basic and Java are notable examples of programming languages that generate an intermediate language. Microsoft's .NET and Common Language Infrastructure (CLI), the ECMA standard version of .NET, also generate an intermediate language (see CLR and CLI). See Java Virtual Machine, bytecode, managed code and runtime environment.

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