A Preliminary Report on the Embedded Virtual Machine

XGIOTTO [5] is a domain specific language for the implementation of embedded software applications with hard temporal constraints. The language is an extension of the original GIOTTO language [6]. In this report we present the XGIOTTO tool chain, composed of the compiler and a specialized virtual machine, Embedded Virtual Machine (EVM). The compiler checks for determinism (absence of races) and time safety (schedulability within logical execution times) and generates code for EVM. The EVM integrates an event filter (which handles aperiodic asynchronous events and event scoping introduced in [5]) and a modified Embedded Machine [7]. The report presents the instruction set and the operational semantics of the virtual machine. The report also presents event calculus which is used to extend expressiveness of XGIOTTO. The report concludes with a case study of implementing an automotive engine controller.