diff --git a/src/debugger/eval.rs b/src/debugger/eval.rs
index aeb0ca5..a3cb3ac 100644
--- a/src/debugger/eval.rs
+++ b/src/debugger/eval.rs
@@ -1,19 +1,17 @@
 use miette::Result;
 
 use crate::{
-    air::AirStmt,
-    lexer::{cursor::Cursor, TokenKind},
+    air::{AirStmt, AsmLine},
     runtime::RunState,
-    symbol::InstrKind,
     AsmParser,
 };
 
-pub fn run(state: &mut RunState, line: String) {
-    let stmt = parse(line);
-
-    println!("{:#?}", stmt);
-
-    todo!();
+pub fn run(state: &mut RunState, line: String) -> Result<()> {
+    let stmt = parse(line)?;
+    let line = AsmLine::new(0, stmt);
+    let instr = line.emit()?;
+    execute(state, instr);
+    Ok(())
 }
 
 fn parse(line: String) -> Result<AirStmt> {
@@ -21,10 +19,12 @@ fn parse(line: String) -> Result<AirStmt> {
     let line = Box::leak(line.into_boxed_str());
 
     let mut parser = AsmParser::new_simple(line)?;
-
     let stmt = parser.parse_simple()?;
 
-    println!("{:#?}", stmt);
+    Ok(stmt)
+}
 
-    todo!();
+fn execute(state: &mut RunState, instr: u16) {
+    let opcode = (instr >> 12) as usize;
+    RunState::OP_TABLE[opcode](state, instr);
 }
diff --git a/src/debugger/mod.rs b/src/debugger/mod.rs
index 83269a9..6c26875 100644
--- a/src/debugger/mod.rs
+++ b/src/debugger/mod.rs
@@ -341,7 +341,9 @@ impl Debugger {
             Command::Eval { instruction } => {
                 self.was_pc_changed = true;
                 dprintln!(Always, "Eval: <{}>", instruction);
-                eval::run(state, instruction);
+                if let Err(err) = eval::run(state, instruction) {
+                    eprintln!("{:?}", err);
+                }
             }
 
             Command::BreakAdd { location } => {
diff --git a/src/parser.rs b/src/parser.rs
index 7489377..6e2645d 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -88,20 +88,17 @@ fn preprocess_simple(src: &'static str) -> Result<Vec<Token>> {
     loop {
         let token = cur.advance_real()?;
         match token.kind {
-            TokenKind::Instr(_) | TokenKind::Trap(_) => res.push(token),
+            TokenKind::Dir(_) => {
+                // TODO(feat): Handle error
+                panic!("unexpected directive");
+            }
 
+            TokenKind::Byte(_) => unreachable!("Found byte in stream"),
+            TokenKind::Breakpoint => unreachable!("Found breakpoint in stream"),
             TokenKind::Comment | TokenKind::Whitespace => continue,
             TokenKind::Eof => break,
 
-            TokenKind::Dir(_)
-            | TokenKind::Label
-            | TokenKind::Lit(_)
-            | TokenKind::Reg(_)
-            | TokenKind::Byte(_)
-            | TokenKind::Breakpoint => {
-                // TODO(feat): Handle error
-                panic!("unexpected token `{:?}`", token.kind);
-            }
+            _ => res.push(token),
         }
     }
 
@@ -240,7 +237,7 @@ impl AsmParser {
     pub fn parse_simple(&mut self) -> Result<AirStmt> {
         let Some(tok) = self.toks.next() else {
             // TODO(feat): Handle error
-            panic!("unexpected eof (possibly unreachable)");
+            panic!("unexpected eof");
         };
 
         match tok.kind {
diff --git a/src/runtime.rs b/src/runtime.rs
index 28451a1..4a6a554 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -173,7 +173,7 @@ impl RunEnvironment {
 }
 
 impl RunState {
-    const OP_TABLE: [fn(&mut RunState, u16); 16] = [
+    pub const OP_TABLE: [fn(&mut RunState, u16); 16] = [
         Self::br,    // 0x0
         Self::add,   // 0x1
         Self::ld,    // 0x2