diff --git a/src/lang/Nub.Lang/Frontend/Generation/Generator.cs b/src/lang/Nub.Lang/Frontend/Generation/Generator.cs
index 3c34824..c32136b 100644
--- a/src/lang/Nub.Lang/Frontend/Generation/Generator.cs
+++ b/src/lang/Nub.Lang/Frontend/Generation/Generator.cs
@@ -299,25 +299,30 @@ public class Generator
         {
             var parameterName = parameter.Name;
 
-            // switch (QBEType(parameter.Type))
-            // {
-            //     case "sb":
-            //         parameterName = GenVarName();
-            //         _builder.AppendLine($"    {parameterName} =w extsb %{parameter.Name}");
-            //         break;
-            //     case "ub":
-            //         parameterName = GenVarName();
-            //         _builder.AppendLine($"    {parameterName} =w extub %{parameter.Name}");
-            //         break;
-            //     case "sh":
-            //         parameterName = GenVarName();
-            //         _builder.AppendLine($"    {parameterName} =w extsh %{parameter.Name}");
-            //         break;
-            //     case "uh":
-            //         parameterName = GenVarName();
-            //         _builder.AppendLine($"    {parameterName} =w extuh %{parameter.Name}");
-            //         break;
-            // }
+            if (parameter.Type is NubPrimitiveType primitiveType)
+            {
+                switch (primitiveType.Kind)
+                {
+                    case PrimitiveTypeKind.I16:
+                        parameterName = GenVarName();
+                        _builder.AppendLine($"    {parameterName} =w extsh %{parameter.Name}");
+                        break;
+                    case PrimitiveTypeKind.I8:
+                        parameterName = GenVarName();
+                        _builder.AppendLine($"    {parameterName} =w extsb %{parameter.Name}");
+                        break;
+                    case PrimitiveTypeKind.U16:
+                        parameterName = GenVarName();
+                        _builder.AppendLine($"    {parameterName} =w extuh %{parameter.Name}");
+                        break;
+                    case PrimitiveTypeKind.U8:
+                        parameterName = GenVarName();
+                        _builder.AppendLine($"    {parameterName} =w extub %{parameter.Name}");
+                        break;
+                    default:
+                        throw new ArgumentOutOfRangeException();
+                }
+            }
 
             if (IsLargeType(parameter.Type))
             {