@@ -17,7 +17,12 @@ jobs:
       matrix:
         os: [windows, ubuntu, macos]
         python: ["3.6", "3.7", "3.8", "3.9", "3.10"]
-        platform: [x64]
+        platform: [x64, x86]
+        exclude:
+          - os: ubuntu
+            platform: x86
+          - os: macos
+            platform: x86
 
     steps:
       - name: Set Environment on macOS
@@ -67,6 +72,7 @@ jobs:
         run: pytest --runtime mono
 
       - name: Python Tests (.NET Core)
+        if: ${{ matrix.platform == 'x64' }}
         run: pytest --runtime netcore
 
       - name: Python Tests (.NET Framework)
@@ -77,7 +83,7 @@ jobs:
         run: dotnet test --runtime any-${{ matrix.platform }} src/python_tests_runner/
 
       - name: Perf tests
-        if: ${{ matrix.python == '3.8' }}
+        if: ${{ (matrix.python == '3.8') && (matrix.platform == 'x64') }}
         run: |
           pip install --force --no-deps --target src/perf_tests/baseline/ pythonnet==2.5.2
           dotnet test --configuration Release --runtime any-${{ matrix.platform }} --logger "console;verbosity=detailed" src/perf_tests/
 
@@ -10,7 +10,7 @@ struct NativeTypeSpec : IDisposable
         public readonly StrPtr Name;
         public readonly int BasicSize;
         public readonly int ItemSize;
-        public readonly IntPtr Flags;
+        public readonly int Flags;
         public IntPtr Slots;
 
         public NativeTypeSpec(TypeSpec spec)
@@ -20,7 +20,7 @@ public NativeTypeSpec(TypeSpec spec)
             this.Name = new StrPtr(spec.Name, Encoding.UTF8);
             this.BasicSize = spec.BasicSize;
             this.ItemSize = spec.ItemSize;
-            this.Flags = new IntPtr((long)spec.Flags);
+            this.Flags = (int)spec.Flags;
 
             unsafe
             {
 
@@ -86,7 +86,11 @@ def pytest_configure(config):
     else:
         domain_tests_dir = os.path.join(os.path.dirname(__file__), "domain_tests")
         bin_path = os.path.join(domain_tests_dir, "bin")
-        check_call(["dotnet", "build", domain_tests_dir, "-o", bin_path])
+        build_cmd = ["dotnet", "build", domain_tests_dir, "-o", bin_path]
+        is_64bits = sys.maxsize > 2**32
+        if not is_64bits:
+            build_cmd += ["/p:Prefer32Bit=True"]
+        check_call(build_cmd)