Now parsing and requiring branch delay slot markers.

Fixes #2.

dcb-exe/src/inst/parse/line.rs

@@ -18,6 +18,9 @@ pub struct Line {
 	/// Labels
 	pub labels: Vec<LineLabel>,
 
+	/// Branch delay
+	pub branch_delay: bool,
+
 	/// Instruction
 	pub inst: Option<LineInst>,
 }
@@ -28,11 +31,22 @@ impl Line {
 		let mut line = line.trim();
 
 		// Parse all labels and then the mnemonic
+		let mut branch_delay = false;
 		let mut labels = vec![];
 		let mnemonic = loop {
 			// If the line starts with a comment or is empty, return all labels
 			if line.starts_with('#') || line.is_empty() {
-				return Ok(Self { labels, inst: None });
+				return Ok(Self {
+					labels,
+					branch_delay,
+					inst: None,
+				});
+			}
+
+			// If we get a `+`, it's a branch delay
+			if let Some(rest) = line.strip_prefix('+') {
+				branch_delay = true;
+				line = rest.trim_start();
 			}
 
 			// Parse a name
@@ -41,7 +55,12 @@ impl Line {
 			// Check the character after the name
 			let mut rest = rest.chars();
 			match rest.next() {
-				// If we got ':', add a label and continue
+				// If we get a label after the branch delay, return Err
+				Some(':') if branch_delay => {
+					return Err(ParseLineError::LabelAfterBranchDelay);
+				},
+
+				// Else add the label
 				Some(':') => {
 					line = rest.as_str().trim_start();
 					let label = LineLabel { name: name.to_owned() };
@@ -53,6 +72,7 @@ impl Line {
 				Some('#') | None => {
 					return Ok(Self {
 						labels,
+						branch_delay,
 						inst: Some(LineInst {
 							mnemonic: name.to_owned(),
 							args:     vec![],
@@ -60,12 +80,12 @@ impl Line {
 					});
 				},
 
-				// If we got a space or eof, we found the mnemonic.
-				// On a space, break and parse arguments
+				// If we got a space, we found the mnemonic.
 				Some(' ') => {
 					line = rest.as_str().trim_start();
 					break name.to_owned();
 				},
+
 				_ => return Err(ParseLineError::InvalidNameSuffix),
 			}
 		};
@@ -90,7 +110,11 @@ impl Line {
 				// If we got eof or a comment, return
 				Some('#') | None => {
 					let inst = Some(LineInst { mnemonic, args });
-					return Ok(Self { labels, inst });
+					return Ok(Self {
+						labels,
+						branch_delay,
+						inst,
+					});
 				},
 
 				_ => return Err(ParseLineError::InvalidArgSuffix),

dcb-exe/src/inst/parse/line/error.rs

@@ -1,8 +1,8 @@
 //! Errors
 
+// Imports
 use snailquote::UnescapeError;
 
-
 /// Error for [`Line::parse`](super::Line::parse)
 #[derive(PartialEq, Debug, thiserror::Error)]
 pub enum ParseLineError {
@@ -21,6 +21,10 @@ pub enum ParseLineError {
 	/// Invalid argument suffix
 	#[error("Invalid argument suffix")]
 	InvalidArgSuffix,
+
+	/// Found label after branch delay token
+	#[error("Labels must come before the branch delay token")]
+	LabelAfterBranchDelay,
 }
 
 /// Name parsing error

dcb-tools/dcb-compiler/src/main.rs

@@ -131,7 +131,7 @@ fn main() -> Result<(), anyhow::Error> {
 					.map_err(|err| (n, err))?
 					.size();
 
-				assert!(insts.insert(cur_pos, (n, inst)).is_none());
+				assert!(insts.insert(cur_pos, (n, line.branch_delay, inst)).is_none());
 
 				cur_pos += inst_size;
 			}
@@ -160,17 +160,46 @@ fn main() -> Result<(), anyhow::Error> {
 		.context("Unable to seek stream to beginning of instructions")?;
 
 	// For each instruction, pack it and output it to the file
-	for (&pos, (n, inst)) in &insts {
+	let mut last_inst = None;
+	for (&pos, &(n, branch_delay, ref inst)) in &insts {
 		// Create the context
 		let ctx = Ctx {
 			pos,
 			labels_by_name: &labels_by_name,
 		};
 
+		// If this instruction has a branch delay marker, if the previous instruction wasn't
+		// a jump, return Err
+		if branch_delay && !last_inst.as_ref().map_or(false, Inst::may_jump) {
+			anyhow::bail!(
+				"Unable to parse line {}: Branch delay markers can only be used when the previous instruction is a \
+				 jump",
+				n
+			);
+		}
+
+		// If this instruction doesn't have a branch delay marker, but the previous instruction
+		// was a jump, return Err
+		if !branch_delay && last_inst.as_ref().map_or(false, Inst::may_jump) {
+			anyhow::bail!(
+				"Unable to parse line {}: Must use a branch delay after a jump instruction",
+				n
+			);
+		}
+
 		let inst = Inst::parse(&inst.mnemonic, &inst.args, &ctx)
 			.with_context(|| format!("Unable to compile instruction at {} in line {}", pos, n + 1))?;
 
+		// If we got a pseudo instruction larger than 1 basic instruction after a jump, return Err
+		if branch_delay && inst.size() > 4 {
+			anyhow::bail!(
+				"Unable to parse line {}: Cannot use a pseudo instruction larger than 4 bytes as a branch delay",
+				n
+			);
+		}
+
 		inst.write(&mut output_file).context("Unable to write to file")?;
+		last_inst = Some(inst);
 	}
 
 	let size = output_file.stream_position().context("Unable to get stream position")? - 0x800;

dcb-tools/dcb-decompiler/src/main.rs

@@ -227,12 +227,18 @@ fn main() -> Result<(), anyhow::Error> {
 
 			// If it's standalone, print it by it's own
 			ExeItem::Unknown { insts } => {
+				let mut prev_inst = None;
 				for (pos, inst) in insts {
 					// Write the position
 					if cli.print_inst_pos {
 						print!("{pos}: ");
 					}
 
+					// If we had a branch / jump instruction before this one, add a "+ "
+					if prev_inst.as_ref().map_or(false, Inst::may_jump) {
+						print!("+ ");
+					}
+
 					// Write the instruction
 					print!(
 						"{}",
@@ -240,6 +246,8 @@ fn main() -> Result<(), anyhow::Error> {
 					);
 
 					println!();
+
+					prev_inst = Some(inst);
 				}
 			},
 		}

resources/game_funcs.yaml

@@ -230,7 +230,7 @@
   inline_comments:
     0x80061910: "args: ($s1, $s0, c & 0xffff, d & 0xffff)"
   start_pos: 0x800618e4
-  end_pos: 0x80061954
+  end_pos: 0x80061958
   kind: Known
 
 - name: modify_spu_delay1
@@ -847,6 +847,42 @@
   end_pos: 0x8004b394
   kind: Known
 
+- name: something43
+  labels:
+    0x8002d0f4: "0"
+    0x8002d104: "1"
+    0x8002d110: "2"
+    0x8002d120: "3"
+    0x8002d130: "4"
+  start_pos: 0x8002d0e4
+  end_pos: 0x8002d140
+  kind: Known
+
+- name: something44
+  start_pos: 0x800316a8
+  end_pos: 0x800316b4
+  kind: Known
+
+- name: something45
+  start_pos: 0x80063cb0
+  end_pos: 0x80063cbc
+  kind: Known
+
+- name: something46
+  start_pos: 0x80063cc4
+  end_pos: 0x80063cd0
+  kind: Known
+
+- name: something47
+  start_pos: 0x80063cd8
+  end_pos: 0x80063ce4
+  kind: Known
+
+- name: something48
+  start_pos: 0x80063d04
+  end_pos: 0x80063d10
+  kind: Known
+
 # A functions
 - name: InitHeap
   signature: "fn(addr: *u32, size: u32)"