Virtual Machines: Memory Management and Control Flow

This lecture discusses the architecture and functioning of virtual machines, focusing on the CEK machine as an extension of the CK machine. The instructor explains how the CEK machine incorporates an environment to manage memory and variables, allowing for the modeling of mutation in programming languages. The lecture covers the semantics of state transitions in the CEK machine, emphasizing the importance of memory safety and the challenges associated with it. The distinction between expressions and statements is highlighted, illustrating how different programming paradigms handle assignments. The instructor also introduces the von Neumann architecture, detailing the components of a CPU and how programs are executed as sequences of instructions. The lecture further explores control flow, including branching and function calls, and discusses intermediate representations in compilers, comparing stack machines and unlimited register machines. The trade-offs between simplicity and performance in virtual machines are examined, concluding with the advantages of using virtual machines for portability and safety in programming.