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WIP, implementing macros

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This commit is contained in:
Ross Andrews
2022-04-05 18:05:24 -05:00
parent 2a9a92a0c8
commit dec2d22b80
6 changed files with 436 additions and 155 deletions
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vasm/src/vasm_evaluator.rs
+59 -44
View File
@@ -1,14 +1,15 @@
use crate::ast::{Node, Operator};
use crate::ast::{Node, Operator, Scope};
use std::collections::BTreeMap;
use std::fmt::{Display, Formatter};
#[derive(Debug, Clone, PartialEq)]
pub enum EvalError<'a> {
MissingLabel(&'a str),
UnknownAddress(i32),
pub enum EvalError {
MissingLabel(String),
UnknownAddress(usize),
OffsetError(usize, i32),
}
impl<'a> Display for EvalError<'a> {
impl Display for EvalError {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
match self {
EvalError::MissingLabel(label) => write!(f, "Unable to resolve label {}", label),
@@ -17,11 +18,20 @@ impl<'a> Display for EvalError<'a> {
"Unable to calculate starting address of line {}",
line_num
),
EvalError::OffsetError(line_num, offset) => {
write!(f, "Invalid line offset {} on line {}", offset, line_num)
}
}
}
}
pub type Scope<'a> = BTreeMap<&'a str, i32>;
fn offset_line(line_num: usize, offset: i32) -> Result<usize, EvalError> {
if (line_num as i32) + offset < 0 {
Err(EvalError::OffsetError(line_num, offset))
} else {
Ok(((line_num as i32) + offset) as usize)
}
}
/// ## Evaluating expressions
/// Now that we have a parsed file, that file has a bunch of numeric symbols in it: labels,
@@ -45,21 +55,22 @@ pub type Scope<'a> = BTreeMap<&'a str, i32>;
/// - If the node is an absolute or relative line offset, it attempts to look up the start of
/// the given line in the table of line start addresses and gives that address relatively or
/// absolutely.
pub fn eval<'a>(
node: &Node<'a>,
line_num: i32,
line_addresses: &BTreeMap<i32, i32>,
pub fn eval(
node: &Node,
line_num: usize,
line_addresses: &BTreeMap<usize, i32>,
scope: &Scope,
) -> Result<i32, EvalError<'a>> {
) -> Result<i32, EvalError> {
match node {
Node::Number(n) => Ok(*n),
Node::Label(label) => scope
.get(label)
.map_or_else(|| Err(EvalError::MissingLabel(label)), |val| Ok(*val)),
Node::Label(label) => scope.get(label.into()).map_or_else(
|| Err(EvalError::MissingLabel(label.to_string())),
|val| Ok(*val),
),
Node::RelativeLabel(label) => {
if let Some(address) = line_addresses.get(&line_num) {
scope.get(label).map_or_else(
|| Err(EvalError::MissingLabel(label)),
scope.get(label.into()).map_or_else(
|| Err(EvalError::MissingLabel(label.to_string())),
|val| Ok(*val - address),
)
} else {
@@ -67,20 +78,21 @@ pub fn eval<'a>(
}
}
Node::AbsoluteOffset(offset) => {
if let Some(dest_address) = line_addresses.get(&(line_num + offset)) {
let addr = offset_line(line_num, *offset)?;
if let Some(dest_address) = line_addresses.get(&addr) {
Ok(*dest_address)
} else {
Err(EvalError::UnknownAddress(line_num + offset))
Err(EvalError::UnknownAddress(addr))
}
}
Node::RelativeOffset(offset) => {
if let (Some(line_address), Some(dest_address)) = (
line_addresses.get(&line_num),
line_addresses.get(&(line_num + offset)),
) {
let addr = offset_line(line_num, *offset)?;
if let (Some(line_address), Some(dest_address)) =
(line_addresses.get(&line_num), line_addresses.get(&addr))
{
Ok(*dest_address - *line_address)
} else {
Err(EvalError::UnknownAddress(line_num + offset))
Err(EvalError::UnknownAddress(addr))
}
}
Node::Expr(car, cdr) => {
@@ -114,25 +126,22 @@ mod test {
test_scope_addresses_eval(BTreeMap::new(), [(1, 0x400)].into(), line)
}
fn test_scope_eval<'a>(
scope: BTreeMap<&'a str, i32>,
line: &'a str,
) -> Result<i32, EvalError<'a>> {
fn test_scope_eval(scope: Scope, line: &str) -> Result<i32, EvalError> {
test_scope_addresses_eval(scope, [(1, 0x400)].into(), line)
}
fn test_addresses_eval(
line_addresses: BTreeMap<i32, i32>,
line_addresses: BTreeMap<usize, i32>,
line: &str,
) -> Result<i32, EvalError> {
test_scope_addresses_eval([].into(), line_addresses, line)
}
fn test_scope_addresses_eval<'a>(
scope: BTreeMap<&'a str, i32>,
line_addresses: BTreeMap<i32, i32>,
line: &'a str,
) -> Result<i32, EvalError<'a>> {
fn test_scope_addresses_eval(
scope: Scope,
line_addresses: BTreeMap<usize, i32>,
line: &str,
) -> Result<i32, EvalError> {
if let Ok(VASMLine::Instruction(_, _, Some(arg))) = parse_vasm_line(line) {
eval(&arg, 1, &line_addresses, &scope)
} else {
@@ -152,45 +161,51 @@ mod test {
#[test]
fn test_labels() {
assert_eq!(test_scope_eval([("apple", 5)].into(), "add apple"), Ok(5));
assert_eq!(
test_scope_eval([("apple", 5)].into(), "add apple + 7"),
test_scope_eval([("apple".into(), 5)].into(), "add apple"),
Ok(5)
);
assert_eq!(
test_scope_eval([("apple".into(), 5)].into(), "add apple + 7"),
Ok(12)
);
assert_eq!(
test_scope_eval([("apple", 5)].into(), "add 5 + apple"),
test_scope_eval([("apple".into(), 5)].into(), "add 5 + apple"),
Ok(10)
);
assert_eq!(
test_scope_eval([("apple", 5), ("banana", 3)].into(), "add apple * banana"),
test_scope_eval(
[("apple".into(), 5), ("banana".into(), 3)].into(),
"add apple * banana"
),
Ok(15)
);
assert_eq!(
test_scope_eval([("apple", 5)].into(), "add banana"),
Err(EvalError::MissingLabel("banana"))
test_scope_eval([("apple".into(), 5)].into(), "add banana"),
Err(EvalError::MissingLabel("banana".into()))
);
assert_eq!(
test_scope_eval([].into(), "add apple + 2"),
Err(EvalError::MissingLabel("apple"))
Err(EvalError::MissingLabel("apple".into()))
);
assert_eq!(
test_scope_eval([].into(), "add 2 + apple"),
Err(EvalError::MissingLabel("apple"))
Err(EvalError::MissingLabel("apple".into()))
);
}
#[test]
fn test_relative_labels() {
assert_eq!(
test_scope_eval([("apple", 0x500)].into(), "jmpr @apple"),
test_scope_eval([("apple".into(), 0x500)].into(), "jmpr @apple"),
Ok(0x100)
);
assert_eq!(
test_scope_eval([("apple", 0x300)].into(), "jmpr @apple"),
test_scope_eval([("apple".into(), 0x300)].into(), "jmpr @apple"),
Ok(-256)
);
assert_eq!(
test_scope_addresses_eval([("apple", 0x300)].into(), [].into(), "jmpr @apple"),
test_scope_addresses_eval([("apple".into(), 0x300)].into(), [].into(), "jmpr @apple"),
Err(EvalError::UnknownAddress(1))
);
}