Implementation Techniques for Prolog

                       Andreas Krall
               Institut für Computersprachen
                Technische Universität Wien
                    Argentinierstraße 8
                        A-1040 Wien
              andi@mips.complang.tuwien.ac.at

Abstract

This paper is a short survey about currently used implementation
techniques for Prolog. It gives an introduction to unification and
resolution in Prolog and presents the memory model and a basic
execution model. These models are expanded to the Vienna Abstract
Machine (VAM) with its two versions, the VAM2p and the VAM1p, and
the most famous abstract machine, the Warren Abstract Machine (WAM).
The continuation passing style model of Prolog, binary Prolog, leads
to the BinWAM. Abstract interpretation can be applied to gather
information about a program. This information is used in the
generation of very specialized machine code and in optimizations
like clause indexing and instruction scheduling on each kind of
abstract machine.