devraza/tinypc
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feat: proper branching and support for instruction-line loops

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Branching works through changing the value of the program counter, which
represents the line number to process.
This commit is contained in:
Muhammad Nauman Raza 2025-01-26 09:17:39 +00:00
parent ebc3d6b0a8
commit 8f0da8a7f7
Signed by: devraza
GPG key ID: 91EAD6081011574B
1 changed files with 19 additions and 5 deletions
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22
src/main.rs
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@ -7,10 +7,19 @@ fn process(
accumulator: &mut i64, accumulator: &mut i64,
memory: &mut HashMap<String, i64>, memory: &mut HashMap<String, i64>,
labels: &HashMap<String, usize>, labels: &HashMap<String, usize>,
pc: &mut usize,
) -> usize { ) -> usize {
let ops: Vec<String> = line.trim().split_whitespace().map(String::from).collect(); let ops: Vec<String> = line.trim().split_whitespace().map(String::from).collect();
match ops[0].as_str() { let options: Vec<&str>;
if ops.len() > 1 {
options = vec![ops[0].as_str(), ops[1].as_str()];
} else {
options = vec![ops[0].as_str()];
}
for op in options {
match op {
"INP" => { "INP" => {
let mut s = String::new(); let mut s = String::new();
io::stdin().read_line(&mut s).unwrap(); io::stdin().read_line(&mut s).unwrap();
@ -21,8 +30,12 @@ fn process(
memory.insert(ops[1].clone(), *accumulator); memory.insert(ops[1].clone(), *accumulator);
} }
"LDA" => { "LDA" => {
if ops.len() > 1 {
*accumulator = *memory.get(&ops[2]).unwrap_or(&0);
} else {
*accumulator = *memory.get(&ops[1]).unwrap_or(&0); *accumulator = *memory.get(&ops[1]).unwrap_or(&0);
} }
}
"ADD" => { "ADD" => {
if let Ok(value) = ops[1].parse::<i64>() { if let Ok(value) = ops[1].parse::<i64>() {
*accumulator += value; *accumulator += value;
@ -38,7 +51,7 @@ fn process(
} }
} }
"BRA" => { "BRA" => {
return *labels.get(&ops[1]).unwrap_or(&0); *pc = *labels.get(&ops[1]).unwrap();
} }
"HLT" => std::process::exit(0), "HLT" => std::process::exit(0),
_ => { _ => {
@ -50,6 +63,7 @@ fn process(
} }
} }
} }
}
return 0; return 0;
} }
@ -71,7 +85,7 @@ fn main() -> io::Result<()> {
if ops.len() > 1 && ops[1] == "DAT" { if ops.len() > 1 && ops[1] == "DAT" {
labels.insert(ops[0].clone(), index); labels.insert(ops[0].clone(), index);
} else if ops.len() > 1 { } else if ops.len() > 1 {
labels.insert(ops[0].clone(), index); labels.insert(ops[1].clone(), index);
} }
code.push(line); code.push(line);
} }
@ -79,7 +93,7 @@ fn main() -> io::Result<()> {
let mut pc: usize = 0; let mut pc: usize = 0;
while pc < code.len() { while pc < code.len() {
let line = &code[pc]; let line = &code[pc];
let next_pc = process(line.to_string(), &mut accumulator, &mut memory, &labels); let next_pc = process(line.to_string(), &mut accumulator, &mut memory, &labels, &mut pc);
if next_pc != 0 { if next_pc != 0 {
pc = next_pc; pc = next_pc;
} else { } else {