diff --git a/Tests/SimpleDebugClient/Program.cs b/Tests/SimpleDebugClient/Program.cs
index 9ceb51b..0b63783 100644
--- a/Tests/SimpleDebugClient/Program.cs
+++ b/Tests/SimpleDebugClient/Program.cs
@@ -17,7 +17,7 @@ internal class Program
 
         Debugger = new ZmqDebuggerClient(connectionString);
         Debugger.DispatcherStep += Debugger_DispatcherStep;
-        Debugger.InterpreterStep += Debugger_InterpreterStep;
+        //Debugger.InterpreterStep += Debugger_InterpreterStep;
 
         Console.WriteLine("Listening for debug messages. Press Ctrl-C to exit.");
         Console.ReadLine();
@@ -36,6 +36,6 @@ internal class Program
 
     private static void Debugger_InterpreterStep(object? sender, InterpreterEntry e)
     {
-        Console.WriteLine(e);
+        
     }
 }
\ No newline at end of file
diff --git a/Tests/SimpleIrisApp/Program.cs b/Tests/SimpleIrisApp/Program.cs
index 913e393..349263a 100644
--- a/Tests/SimpleIrisApp/Program.cs
+++ b/Tests/SimpleIrisApp/Program.cs
@@ -20,6 +20,8 @@ internal class Program
 
         Application.DebugSettings.DebugConnectionUri = args.Length >= 2
             ? args[1] : "tcp://127.0.0.1:5556";
+
+        Application.DebugSettings.Breakpoints.Add(new("clr-res://SimpleIrisApp!MainPage.uix", 3, 22));
 #endif
 
         Console.WriteLine("Initializing Iris...");
diff --git a/UIX/Microsoft/Iris/Markup/Interpreter.cs b/UIX/Microsoft/Iris/Markup/Interpreter.cs
index 9f0b7e7..db2cca2 100644
--- a/UIX/Microsoft/Iris/Markup/Interpreter.cs
+++ b/UIX/Microsoft/Iris/Markup/Interpreter.cs
@@ -73,6 +73,16 @@ namespace Microsoft.Iris.Markup
                 OpCode opCode = (OpCode)reader.ReadByte();
                 Debug.Data.InterpreterEntry entry = new(opCode);
 
+                // Fetch line and column numbers from the table
+                if (debugging && context.LoadResult.LineNumberTable.TryLookup(reader.CurrentOffset, out int line, out int column))
+                {
+                    // Check if a breakpoint has been set at this location
+                    bool shouldBreak = Application.DebugSettings.Breakpoints
+                        .Any(b => b.Line == line && b.Column == column && b.Uri.Equals(loadResult.Uri, StringComparison.OrdinalIgnoreCase));
+                    if (shouldBreak)
+                        System.Diagnostics.Debugger.Break();
+                }
+
                 switch (opCode)
                 {
                     case OpCode.ConstructObject:
diff --git a/UIX/Microsoft/Iris/Markup/InterpreterContext.cs b/UIX/Microsoft/Iris/Markup/InterpreterContext.cs
index e5fd7b0..103aafd 100644
--- a/UIX/Microsoft/Iris/Markup/InterpreterContext.cs
+++ b/UIX/Microsoft/Iris/Markup/InterpreterContext.cs
@@ -31,7 +31,7 @@ namespace Microsoft.Iris.Markup
             uint currentOffset = _loadResult.ObjectSection.CurrentOffset;
             if (currentOffset > 0U)
                 --currentOffset;
-            _loadResult.LineNumberTable.Lookup(currentOffset, out line, out column);
+            _loadResult.LineNumberTable.TryLookup(currentOffset, out line, out column);
         }
 
         public IMarkupTypeBase Instance => _instance;
diff --git a/UIX/Microsoft/Iris/Markup/MarkupLineNumberTable.cs b/UIX/Microsoft/Iris/Markup/MarkupLineNumberTable.cs
index cc9a09d..21c03ad 100644
--- a/UIX/Microsoft/Iris/Markup/MarkupLineNumberTable.cs
+++ b/UIX/Microsoft/Iris/Markup/MarkupLineNumberTable.cs
@@ -42,7 +42,7 @@ namespace Microsoft.Iris.Markup
             _lookupTable = null;
         }
 
-        public void Lookup(uint offset, out int line, out int column)
+        public bool TryLookup(uint offset, out int line, out int column)
         {
             int length = _runtimeList.Length;
             int index = 0;
@@ -52,11 +52,13 @@ namespace Microsoft.Iris.Markup
             {
                 line = UnpackLine(_runtimeList[index]);
                 column = UnpackColumn(_runtimeList[index]);
+                return true;
             }
             else
             {
                 line = -1;
                 column = -1;
+                return false;
             }
         }
 
@@ -69,10 +71,10 @@ namespace Microsoft.Iris.Markup
 
         private static ulong Pack(uint offset, int line, int column) => (ulong)(offset | (long)line << 22 | (long)column << 43);
 
-        private static uint UnpackOffset(ulong value) => (uint)(value & 4194303UL);
+        private static uint UnpackOffset(ulong value) => (uint)(value & 0x3F_FFFFUL);
 
-        private static int UnpackLine(ulong value) => (int)((value & 8796088827904UL) >> 22);
+        private static int UnpackLine(ulong value) => (int)((value & 0x7FF_FFC0_0000UL) >> 22);
 
-        private static int UnpackColumn(ulong value) => (int)((value & 18446735277616529408UL) >> 43);
+        private static int UnpackColumn(ulong value) => (int)((value & 0xFFFF_F800_0000_0000UL) >> 43);
     }
 }