Denotational Model and Implementation of Scalable Virtual Machine in CPDev

Denotational semantic model and its implementation in C/C++ are presented for a virtual machine executing programs written in the CPDev development environment according to IEC 61131 standard. Programs written in IEC ST language are compiled to control-oriented intermediate language designed specifically for the machine. Architecture of the machine and its operation are represented by formal semantic model which assigns abstract algebraic objects to denote machine behaviour. Execution of intermediate language instructions is described in details by denotational semantic equations followed strictly by C/C++ implementations to assure reliability of the machine.