forked from koniifer/ableos
Erin
06b1184772
- Changed instruction encoding to be faster to match on - Implemented all instructions defined in spec - Bytecode validation - Assembler - Implemented 5 level paging (based on SV57) - Implemented some degree of interrupts (though not fully adhering the spec yet)
309 lines
12 KiB
Rust
309 lines
12 KiB
Rust
//! HoleyBytes Virtual Machine
|
|
//!
|
|
//! All unsafe code here should be sound, if input bytecode passes validation.
|
|
|
|
// # General safety notice:
|
|
// - Validation has to assure there is 256 registers (r0 - r255)
|
|
// - Instructions have to be valid as specified (values and sizes)
|
|
// - Mapped pages should be at least 4 KiB
|
|
// - Yes, I am aware of the UB when jumping in-mid of instruction where
|
|
// the read byte corresponds to an instruction whose lenght exceets the
|
|
// program size. If you are (rightfully) worried about the UB, for now just
|
|
// append your program with 11 zeroes.
|
|
|
|
mod mem;
|
|
mod value;
|
|
|
|
use {
|
|
crate::validate,
|
|
core::ops,
|
|
hbbytecode::{OpParam, ParamBB, ParamBBB, ParamBBBB, ParamBBD, ParamBBDH, ParamBD},
|
|
mem::Memory,
|
|
static_assertions::assert_impl_one,
|
|
value::Value,
|
|
};
|
|
|
|
macro_rules! param {
|
|
($self:expr, $ty:ty) => {{
|
|
assert_impl_one!($ty: OpParam);
|
|
let data = $self
|
|
.program
|
|
.as_ptr()
|
|
.add($self.pc + 1)
|
|
.cast::<$ty>()
|
|
.read();
|
|
$self.pc += 1 + core::mem::size_of::<$ty>();
|
|
data
|
|
}};
|
|
}
|
|
|
|
macro_rules! binary_op {
|
|
($self:expr, $ty:ident, $handler:expr) => {{
|
|
let ParamBBB(tg, a0, a1) = param!($self, ParamBBB);
|
|
$self.write_reg(
|
|
tg,
|
|
$handler(
|
|
Value::$ty(&$self.read_reg(a0)),
|
|
Value::$ty(&$self.read_reg(a1)),
|
|
)
|
|
.into(),
|
|
);
|
|
}};
|
|
}
|
|
|
|
macro_rules! binary_op_imm {
|
|
($self:expr, $ty:ident, $handler:expr) => {{
|
|
let ParamBBD(tg, a0, imm) = param!($self, ParamBBD);
|
|
$self.write_reg(
|
|
tg,
|
|
$handler(Value::$ty(&$self.read_reg(a0)), Value::$ty(&imm.into())).into(),
|
|
);
|
|
}};
|
|
}
|
|
|
|
macro_rules! cond_jump {
|
|
($self:expr, $ty:ident, $expected:ident) => {{
|
|
let ParamBBD(a0, a1, jt) = param!($self, ParamBBD);
|
|
if core::cmp::Ord::cmp(&$self.read_reg(a0).as_u64(), &$self.read_reg(a1).as_u64())
|
|
== core::cmp::Ordering::$expected
|
|
{
|
|
$self.pc = jt as usize;
|
|
}
|
|
}};
|
|
}
|
|
|
|
pub struct Vm<'a> {
|
|
pub registers: [Value; 256],
|
|
pub memory: Memory,
|
|
pc: usize,
|
|
program: &'a [u8],
|
|
}
|
|
|
|
impl<'a> Vm<'a> {
|
|
/// # Safety
|
|
/// Program code has to be validated
|
|
pub unsafe fn new_unchecked(program: &'a [u8]) -> Self {
|
|
Self {
|
|
registers: [Value::from(0_u64); 256],
|
|
memory: Default::default(),
|
|
pc: 0,
|
|
program,
|
|
}
|
|
}
|
|
|
|
pub fn new_validated(program: &'a [u8]) -> Result<Self, validate::Error> {
|
|
validate::validate(program)?;
|
|
Ok(unsafe { Self::new_unchecked(program) })
|
|
}
|
|
|
|
pub fn run(&mut self) -> HaltReason {
|
|
use hbbytecode::opcode::*;
|
|
loop {
|
|
let Some(&opcode) = self.program.get(self.pc)
|
|
else { return HaltReason::ProgramEnd };
|
|
|
|
unsafe {
|
|
match opcode {
|
|
NOP => param!(self, ()),
|
|
ADD => binary_op!(self, as_u64, u64::wrapping_add),
|
|
SUB => binary_op!(self, as_u64, u64::wrapping_sub),
|
|
MUL => binary_op!(self, as_u64, u64::wrapping_mul),
|
|
AND => binary_op!(self, as_u64, ops::BitAnd::bitand),
|
|
OR => binary_op!(self, as_u64, ops::BitOr::bitor),
|
|
XOR => binary_op!(self, as_u64, ops::BitXor::bitxor),
|
|
SL => binary_op!(self, as_u64, ops::Shl::shl),
|
|
SR => binary_op!(self, as_u64, ops::Shr::shr),
|
|
SRS => binary_op!(self, as_i64, ops::Shr::shr),
|
|
CMP => {
|
|
let ParamBBB(tg, a0, a1) = param!(self, ParamBBB);
|
|
self.write_reg(
|
|
tg,
|
|
(self.read_reg(a0).as_i64().cmp(&self.read_reg(a1).as_i64()) as i64)
|
|
.into(),
|
|
);
|
|
}
|
|
CMPU => {
|
|
let ParamBBB(tg, a0, a1) = param!(self, ParamBBB);
|
|
self.write_reg(
|
|
tg,
|
|
(self.read_reg(a0).as_u64().cmp(&self.read_reg(a1).as_u64()) as i64)
|
|
.into(),
|
|
);
|
|
}
|
|
NOT => {
|
|
let param = param!(self, ParamBB);
|
|
self.write_reg(param.0, (!self.read_reg(param.1).as_u64()).into());
|
|
}
|
|
NEG => {
|
|
let param = param!(self, ParamBB);
|
|
self.write_reg(
|
|
param.0,
|
|
match self.read_reg(param.1).as_u64() {
|
|
0 => 1_u64,
|
|
_ => 0,
|
|
}
|
|
.into(),
|
|
);
|
|
}
|
|
DIR => {
|
|
let ParamBBBB(dt, rt, a0, a1) = param!(self, ParamBBBB);
|
|
let a0 = self.read_reg(a0).as_u64();
|
|
let a1 = self.read_reg(a1).as_u64();
|
|
self.write_reg(dt, (a0.checked_div(a1).unwrap_or(u64::MAX)).into());
|
|
self.write_reg(rt, (a0.checked_rem(a1).unwrap_or(u64::MAX)).into());
|
|
}
|
|
ADDI => binary_op_imm!(self, as_u64, ops::Add::add),
|
|
MULI => binary_op_imm!(self, as_u64, ops::Mul::mul),
|
|
ANDI => binary_op_imm!(self, as_u64, ops::BitAnd::bitand),
|
|
ORI => binary_op_imm!(self, as_u64, ops::BitOr::bitor),
|
|
XORI => binary_op_imm!(self, as_u64, ops::BitXor::bitxor),
|
|
SLI => binary_op_imm!(self, as_u64, ops::Shl::shl),
|
|
SRI => binary_op_imm!(self, as_u64, ops::Shr::shr),
|
|
SRSI => binary_op_imm!(self, as_i64, ops::Shr::shr),
|
|
CMPI => {
|
|
let ParamBBD(tg, a0, imm) = param!(self, ParamBBD);
|
|
self.write_reg(
|
|
tg,
|
|
(self.read_reg(a0).as_i64().cmp(&Value::from(imm).as_i64()) as i64)
|
|
.into(),
|
|
);
|
|
}
|
|
CMPUI => {
|
|
let ParamBBD(tg, a0, imm) = param!(self, ParamBBD);
|
|
self.write_reg(tg, (self.read_reg(a0).as_u64().cmp(&imm) as i64).into());
|
|
}
|
|
CP => {
|
|
let param = param!(self, ParamBB);
|
|
self.write_reg(param.0, self.read_reg(param.1));
|
|
}
|
|
SWA => {
|
|
let ParamBB(src, dst) = param!(self, ParamBB);
|
|
if src + dst != 0 {
|
|
core::ptr::swap(
|
|
self.registers.get_unchecked_mut(usize::from(src)),
|
|
self.registers.get_unchecked_mut(usize::from(dst)),
|
|
);
|
|
}
|
|
}
|
|
LI => {
|
|
let param = param!(self, ParamBD);
|
|
self.write_reg(param.0, param.1.into());
|
|
}
|
|
LD => {
|
|
let ParamBBDH(dst, base, off, count) = param!(self, ParamBBDH);
|
|
let n: usize = match dst {
|
|
0 => 1,
|
|
_ => 0,
|
|
};
|
|
|
|
if self
|
|
.memory
|
|
.load(
|
|
self.read_reg(base).as_u64() + off + n as u64,
|
|
self.registers.as_mut_ptr().add(usize::from(dst) + n).cast(),
|
|
usize::from(count).saturating_sub(n),
|
|
)
|
|
.is_err()
|
|
{
|
|
return HaltReason::LoadAccessEx;
|
|
}
|
|
}
|
|
ST => {
|
|
let ParamBBDH(dst, base, off, count) = param!(self, ParamBBDH);
|
|
if self
|
|
.memory
|
|
.store(
|
|
self.read_reg(base).as_u64() + off,
|
|
self.registers.as_ptr().add(usize::from(dst)).cast(),
|
|
count.into(),
|
|
)
|
|
.is_err()
|
|
{
|
|
return HaltReason::LoadAccessEx;
|
|
}
|
|
}
|
|
BMC => {
|
|
let ParamBBD(src, dst, count) = param!(self, ParamBBD);
|
|
if self
|
|
.memory
|
|
.block_copy(
|
|
self.read_reg(src).as_u64(),
|
|
self.read_reg(dst).as_u64(),
|
|
count,
|
|
)
|
|
.is_err()
|
|
{
|
|
return HaltReason::LoadAccessEx;
|
|
}
|
|
}
|
|
BRC => {
|
|
let ParamBBB(src, dst, count) = param!(self, ParamBBB);
|
|
core::ptr::copy(
|
|
self.registers.get_unchecked(usize::from(src)),
|
|
self.registers.get_unchecked_mut(usize::from(dst)),
|
|
usize::from(count * 8),
|
|
);
|
|
}
|
|
JMP => {
|
|
let ParamBD(reg, offset) = param!(self, ParamBD);
|
|
self.pc = (self.read_reg(reg).as_u64() + offset) as usize;
|
|
}
|
|
JEQ => cond_jump!(self, int, Equal),
|
|
JNE => {
|
|
let ParamBBD(a0, a1, jt) = param!(self, ParamBBD);
|
|
if self.read_reg(a0).as_u64() != self.read_reg(a1).as_u64() {
|
|
self.pc = jt as usize;
|
|
}
|
|
}
|
|
JLT => cond_jump!(self, int, Less),
|
|
JGT => cond_jump!(self, int, Greater),
|
|
JLTU => cond_jump!(self, sint, Less),
|
|
JGTU => cond_jump!(self, sint, Greater),
|
|
ECALL => {
|
|
param!(self, ());
|
|
return HaltReason::Ecall;
|
|
}
|
|
ADDF => binary_op!(self, as_f64, ops::Add::add),
|
|
MULF => binary_op!(self, as_f64, ops::Mul::mul),
|
|
DIRF => {
|
|
let ParamBBBB(dt, rt, a0, a1) = param!(self, ParamBBBB);
|
|
let a0 = self.read_reg(a0).as_f64();
|
|
let a1 = self.read_reg(a1).as_f64();
|
|
self.write_reg(dt, (a0 / a1).into());
|
|
self.write_reg(rt, (a0 % a1).into());
|
|
}
|
|
ADDFI => binary_op_imm!(self, as_f64, ops::Add::add),
|
|
MULFI => binary_op_imm!(self, as_f64, ops::Mul::mul),
|
|
_ => return HaltReason::InvalidOpcode,
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn read_reg(&self, n: u8) -> Value {
|
|
if n == 0 {
|
|
0_u64.into()
|
|
} else {
|
|
*self.registers.get_unchecked(n as usize)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn write_reg(&mut self, n: u8, value: Value) {
|
|
if n != 0 {
|
|
*self.registers.get_unchecked_mut(n as usize) = value;
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
#[repr(u8)]
|
|
pub enum HaltReason {
|
|
ProgramEnd,
|
|
Ecall,
|
|
InvalidOpcode,
|
|
LoadAccessEx,
|
|
StoreAccessEx,
|
|
}
|