MIDAS: A Formally Constructed Virtual Machine

Abstract

MIDAS (Microprocessor Instruction and Data Abstraction System) is a specification of an Instruction Set Architecture (ISA) capable of executing binary images compiled from the C language. It was developed to demonstrate a methodology for formal construction of various ISAs in Event-B via a generic model. It is intended to be representative of typical microprocessor ISAs, but using a minimal number of defined instructions, in order to make complete refinement practical. The intention is to simplify the number and complexity of the defined instructions at the cost of compiler complexity, run-time performance and code density, without compromising representativeness. There are two variants: a stack-based machine and a randomly accessible register array machine. The two variants employ the same instruction codes, the differences being limited to register file behavior.