The CpuVirtualMachine Class

This class is built for running BEAST byte code programs on the CPU of the host system. Instructions are processed in a linear fashion, and the current execution state is held in an instance of The VmSession Class.

class CpuVirtualMachine : public beast::VirtualMachine

Runs program code in a CPU-based environment.

All operators are executed in a step-by-step CPU-based state machine. No alteration of the program code to execute is applied, and execution is not parallelized. The execution behavior is guaranteed to be deterministic.

Author

Jan Winkler

Date

2022-12-19

Public Functions

~CpuVirtualMachine()

Virtual destructor performing no operation to ensure vtable consistency.

bool step(VmSession &session, bool dry_run)

Executes the next step a program in its current state as denoted by a VM session.

This function must be implemented by subclasses of the VirtualMachine class. A VmSession is passed in that contains a program to execute, and a state at which the program currently is (including instruction pointer, variable memory, and string table).

When the dry_run parameter is passed, the VM is supposed to only step through the operations in a program and not actually execute them. This can be used to count the effective amount and individual types of operators in a program, as well as analyze its structure.

Return

A boolean flag denoting whether the session can further execute instructions.

Parameters

• session: The VmSession instance that holds the program and state to step through.
• dry_run: Determines whether operators are executed or just read.