diff --git a/SourceGen/AddressMap.cs b/CommonUtil/AddressMap.cs
similarity index 98%
rename from SourceGen/AddressMap.cs
rename to CommonUtil/AddressMap.cs
index 05ae8e8..e7e648f 100644
--- a/SourceGen/AddressMap.cs
+++ b/CommonUtil/AddressMap.cs
@@ -18,7 +18,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 
-namespace SourceGen {
+namespace CommonUtil {
     /// <summary>
     /// Map file offsets to 65xx addresses and vice-versa.  Useful for sources with
     /// multiple ORG directives.
@@ -28,6 +28,10 @@ namespace SourceGen {
     /// it's useful to know the offset of the referring code when evaluating a
     /// reference, so that a "local" match can take priority.
     /// </summary>
+    /// <remarks>
+    /// This was part of the main SourceGen application, but I want to share it with
+    /// script extensions.
+    /// </remarks>
     public class AddressMap : IEnumerable<AddressMap.AddressMapEntry> {
         /// <summary>
         /// Code starting at the specified offset will have the specified address.
diff --git a/SourceGen/LineListGen.cs b/SourceGen/LineListGen.cs
index bb4c0d9..b195802 100644
--- a/SourceGen/LineListGen.cs
+++ b/SourceGen/LineListGen.cs
@@ -20,6 +20,7 @@ using System.Windows.Media;
 using System.Text;
 
 using Asm65;
+using CommonUtil;
 using FormattedParts = SourceGen.DisplayList.FormattedParts;
 
 namespace SourceGen {
diff --git a/SourceGen/SourceGen.csproj b/SourceGen/SourceGen.csproj
index 96dac57..d5fd7ef 100644
--- a/SourceGen/SourceGen.csproj
+++ b/SourceGen/SourceGen.csproj
@@ -59,7 +59,6 @@
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </ApplicationDefinition>
-    <Compile Include="AddressMap.cs" />
     <Compile Include="Anattrib.cs" />
     <Compile Include="App.xaml.cs">
       <DependentUpon>App.xaml</DependentUpon>