forked from AbleOS/holey-bytes
69 lines
1.9 KiB
Rust
69 lines
1.9 KiB
Rust
macro_rules! bail {
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($kind:ident, $start:expr, $curr:expr, $offset:expr) => {
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return Err(Error {
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kind: ErrorKind::$kind,
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index: ($curr.as_ptr() as usize) - ($start.as_ptr() as usize) + $offset
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})
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};
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($kind:ident, $start:expr, $curr:expr) => {
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bail!($kind, $start, $curr, 0)
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};
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}
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum ErrorKind {
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InvalidInstruction,
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InvalidRegister,
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Unimplemented,
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}
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub struct Error {
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kind: ErrorKind,
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index: usize,
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}
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pub fn validate(mut program: &[u8]) -> Result<(), Error> {
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use crate::bytecode::opcode::*;
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#[inline]
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fn reg(regs: &[u8]) -> Option<usize> {
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regs.iter()
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.enumerate()
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.filter_map(|(n, &r)| (r > 59).then_some(n))
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.next()
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}
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let start = program;
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loop {
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program = match program {
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[] => return Ok(()),
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// N
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[NOP | RET | ECALL, rest @ ..] => rest,
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// RRR
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[ADD..=XOR | ADDF..=DIVF, _, _, _, rest @ ..] => {
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if let Some(n) = reg(&program[1..=3]) {
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bail!(InvalidRegister, start, program, n + 1)
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}
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rest
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}
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// RR
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[NOT, _, _, rest @ ..] => {
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if let Some(n) = reg(&program[1..=2]) {
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bail!(InvalidRegister, start, program, n + 1)
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}
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rest
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}
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// RI
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[LI, reg, _, _, _, _, _, _, _, _, rest @ ..] => {
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if *reg > 59 {
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bail!(InvalidRegister, start, program, 1)
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}
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rest
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}
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[LD | ST, ..] => bail!(Unimplemented, start, program),
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_ => bail!(InvalidInstruction, start, program),
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}
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}
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}
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