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CW 283
B. Demoen and P.L. Nguyen
Experiments in WAM emulators and term representations
Abstract
Successful Prolog implementations are often based on WAM. While WAM is a very good starting point, it leaves certain issues open and also allows within its framework a lot of variations, optimizations and extensions, e.g. regarding the term representation, the instruction set, the memory organization, the represented data etc. It is therefore no surprise that different implementations of Prolog have successfully exploited in different ways the freedom left by WAM. While successful within their particular context, it is difficult to assess the merit of a particular variation. This work describes an attempt to do exactly that: Within one basic implementation - dProlog, based on WAM and using the XSB compiler - four term representations were implemented and compared. Each of these representations has been used by some successful system, so it is worthwhile to have empirical data on their performance while keeping all other things equal. Still within dProlog, we also report on different choices in the emulator for WAM. Since dProlog is a reasonably efficient Prolog system, it is relevant to measure the impact of these choices.
report.pdf / mailto: B. Demoen