Struct watchmaker_vm::VirtualMachine

pub struct VirtualMachine { /* private fields */ }

A running instance of a virtual machine.

All internal registers are initialized to zero at start up. The type exposes methods to either submit new data (iinput, dinput) or to extract results (ioutput, doutput).

Operand addresses are evaluated modulo the size of the register array they refer to, to keep them within the allocated memory for that array.

This type is not thread safe. However, multiple instances do not share state and so can be used concurrently (for example, one virtual machine instance per thread) without interfering with each other.

Implementations

impl VirtualMachine

pub fn new(architecture: &Architecture, instructions: Vec<Instruction>) -> Self

Create a new instance of a virtual machine. This is the main method exposed by the crate.

Arguments

• architecture - Configuration of memory sizes and other parameters.
• instructions - Instructions to execute.

pub fn run(&mut self, budget: usize)

Call to run the virtual machine until one of the following criteria are met.

Stopping Criteria

• SYN instruction executed. Caller should use results in output memory, update input memory if required and call run again.
• HLT instruction executed. Execution has finished. Caller should use results in output memory and not call run again.
• The maximum number of instructions has been executed. Execution has finished. Caller should use results in output memory and not call run again.

End of code behavior

Code execution will jump back to the first instruction on reaching the end of the provided instructions (ie wraps around). To prevent this behaviour, add a HLT instruction as the last instruction.

Arguments

• budget - The maximum number of instructions to implement.

pub fn iinput(&mut self) -> &mut Vec<i64>

A modifiable bank of integers that act as input to the virtual machine.

pub fn dinput(&mut self) -> &mut Vec<f64>

A bank of floating point values that act as input to the virtual machine.

pub fn ioutput(&self) -> &Vec<i64>

A snapshot of the bank of integers that act as output from the virtual machine.

pub fn doutput(&self) -> &Vec<f64>

A snapshot of the bank of floating point values that act as output from the virtual machine.

pub fn snapshot(&self) -> &Memory

A snapshot copy of the memory of the virtual machine.

pub fn next_instruction(&self) -> &Instruction

The next instruction to execute.

pub fn next_instruction_position(&self) -> usize

The next instruction to execute.

pub fn count(&self) -> u64

The number of instructions executed so far.

Trait Implementations

impl Debug for VirtualMachine

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.