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.
Although the concept was first implemented circa 1966 (as O-code for BCPL and P - a code for the Euler Language, Wirth & Weber, CACM Vol9 No2, 1966), the term p-code first appeared in the early 1970s. Two early compilers generating p-code were the Pascal-P compiler in 1973, by Nori, Ammann, Jensen, Hageli, and Jacobi, and the Pascal-S compiler in 1975, by Niklaus Wirth.
Programs that have been translated to p-code are interpreted by a software program that emulates the behavior of the hypothetical CPU. If there is sufficient commercial interest, a hardware implementation of the CPU specification may be built (e.g., the Pascal MicroEngine or a version of the Java processor).
Read more about P-code Machine: Example Machine
Famous quotes containing the word machine:
“The white man regards the universe as a gigantic machine hurtling through time and space to its final destruction: individuals in it are but tiny organisms with private lives that lead to private deaths: personal power, success and fame are the absolute measures of values, the things to live for. This outlook on life divides the universe into a host of individual little entities which cannot help being in constant conflict thereby hastening the approach of the hour of their final destruction.”
—Policy statement, 1944, of the Youth League of the African National Congress. pt. 2, ch. 4, Fatima Meer, Higher than Hope (1988)