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|
use sloth_bytecode::Instruction;
use crate::{Chunk, Data, Stack};
pub struct VM {
vm_return: Option<Data>,
stack: Stack,
}
impl VM {
fn new() -> Self {
Self {
vm_return: None,
stack: Stack::default(),
}
}
fn execute(&mut self) {
loop {
self.execute_once();
}
}
fn execute_once(&mut self) {
//
}
fn run(&mut self, chunk: &Chunk) {
let mut pointer = 0;
loop {
let instruction = Instruction::disassemble(&chunk.code, &mut pointer);
match instruction {
Instruction::Constant(idx) => {
let value = chunk.constants[idx as usize];
self.stack.push(value);
}
Instruction::Load(_) => todo!(),
Instruction::Push(_) => todo!(),
Instruction::Dup => {
let value = self.stack.pop();
self.stack.push(value);
self.stack.push(value);
}
Instruction::Del => {
self.stack.pop();
}
Instruction::Add => {
let value = match self.stack.pop2() {
(Data::Integer(lhs), Data::Integer(rhs)) => Data::Integer(lhs + rhs),
(Data::Float(lhs), Data::Float(rhs)) => Data::Float(lhs + rhs),
_ => panic!(),
};
self.stack.push(value);
}
Instruction::Sub => {
let value = match self.stack.pop2() {
(Data::Integer(lhs), Data::Integer(rhs)) => Data::Integer(lhs - rhs),
(Data::Float(lhs), Data::Float(rhs)) => Data::Float(lhs - rhs),
_ => panic!(),
};
self.stack.push(value);
}
Instruction::Mul => {
let value = match self.stack.pop2() {
(Data::Integer(lhs), Data::Integer(rhs)) => Data::Integer(lhs * rhs),
(Data::Float(lhs), Data::Float(rhs)) => Data::Float(lhs * rhs),
_ => panic!(),
};
self.stack.push(value);
}
Instruction::Div => {
let value = match self.stack.pop2() {
(Data::Integer(lhs), Data::Integer(rhs)) => Data::Integer(lhs / rhs),
(Data::Float(lhs), Data::Float(rhs)) => Data::Float(lhs / rhs),
_ => panic!(),
};
self.stack.push(value);
}
Instruction::Mod => {
let value = match self.stack.pop2() {
(Data::Integer(lhs), Data::Integer(rhs)) => Data::Integer(lhs % rhs),
(Data::Float(lhs), Data::Float(rhs)) => Data::Float(lhs % rhs),
_ => panic!(),
};
self.stack.push(value);
}
Instruction::Hlt => break,
Instruction::Exit => break,
Instruction::VMReturn => {
let value = self.stack.pop();
self.vm_return = Some(value);
break;
}
_ => unimplemented!(),
}
}
}
}
#[cfg(test)]
mod tests {
use crate::{Chunk, Data, VM};
#[test]
fn arithmetic_ops() {
let mut vm = VM::new();
// Addition
vm.run(&Chunk {
constants: vec![Data::Integer(7)],
code: vec![
0x00, 0, 0, 0, 0, // Load constant from 0
0x10, // Duplicate
0x20, // Add
0xF0, // Return VM
],
});
assert_eq!(vm.vm_return, Some(Data::Integer(14)));
vm.run(&Chunk {
constants: vec![Data::Integer(2), Data::Integer(11)],
code: vec![
0x00, 0, 0, 0, 0, // Load constant from 0
0x00, 0, 0, 0, 1, // Load constant from 1
0x20, // Add
0xF0, // Return VM
],
});
assert_eq!(vm.vm_return, Some(Data::Integer(13)));
}
}
|
