forked from AbleOS/holey-bytes
96 lines
3 KiB
Rust
96 lines
3 KiB
Rust
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mod value;
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use {
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crate::bytecode::{OpParam, ParamRI, ParamRR, ParamRRR},
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core::ops,
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static_assertions::assert_impl_one,
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value::Value,
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};
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macro_rules! param {
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($self:expr, $ty:ty) => {{
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assert_impl_one!($ty: OpParam);
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let data = $self.program.as_ptr()
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.add($self.pc + 1)
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.cast::<$ty>()
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.read();
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$self.pc += 1 + core::mem::size_of::<$ty>();
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data
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}};
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}
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macro_rules! binary_op {
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($self:expr, $ty:ident, $handler:expr) => {{
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let ParamRRR(tg, a0, a1) = param!($self, ParamRRR);
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*$self.reg_mut(tg) = $handler(Value::$ty($self.reg(a0)), Value::$ty($self.reg(a1))).into();
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}};
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}
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pub struct Vm<'a> {
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pub registers: [Value; 60],
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pc: usize,
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program: &'a [u8],
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}
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impl<'a> Vm<'a> {
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/// # Safety
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/// Program code has to be validated
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pub unsafe fn new_unchecked(program: &'a [u8]) -> Self {
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Self {
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registers: [Value::from(0); 60],
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pc: 0,
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program,
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}
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}
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pub fn run(&mut self) {
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use crate::bytecode::opcode::*;
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loop {
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let Some(&opcode) = self.program.get(self.pc)
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else { return };
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unsafe {
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match opcode {
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NOP => param!(self, ()),
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ADD => binary_op!(self, int, u64::wrapping_add),
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SUB => binary_op!(self, int, u64::wrapping_sub),
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MUL => binary_op!(self, int, u64::wrapping_mul),
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DIV => binary_op!(self, int, u64::wrapping_div),
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REM => binary_op!(self, int, u64::wrapping_rem),
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AND => binary_op!(self, int, ops::BitAnd::bitand),
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OR => binary_op!(self, int, ops::BitOr::bitor),
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XOR => binary_op!(self, int, ops::BitXor::bitxor),
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NOT => {
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let param = param!(self, ParamRR);
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*self.reg_mut(param.0) = (!self.reg(param.1).int()).into();
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}
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ADDF => binary_op!(self, float, ops::Add::add),
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SUBF => binary_op!(self, float, ops::Sub::sub),
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MULF => binary_op!(self, float, ops::Mul::mul),
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DIVF => binary_op!(self, float, ops::Div::div),
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LI => {
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let param = param!(self, ParamRI);
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*self.reg_mut(param.0) = param.1.into();
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}
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// TODO: LD, ST
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JMP => {
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self.pc =
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self.program.as_ptr().add(self.pc + 1).cast::<u64>().read() as usize;
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}
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_ => core::hint::unreachable_unchecked(),
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}
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}
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}
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}
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#[inline]
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unsafe fn reg(&self, n: u8) -> &Value {
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self.registers.get_unchecked(n as usize)
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}
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#[inline]
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unsafe fn reg_mut(&mut self, n: u8) -> &mut Value {
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self.registers.get_unchecked_mut(n as usize)
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}
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}
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