diff --git a/include/xo/procedure2/GcPrimitives.hpp b/include/xo/procedure2/GcPrimitives.hpp
index 4b134fd..9b64eca 100644
--- a/include/xo/procedure2/GcPrimitives.hpp
+++ b/include/xo/procedure2/GcPrimitives.hpp
@@ -27,6 +27,10 @@ namespace xo {
             static DPrimitive_gco_0 * make_report_gc_object_types_pm(obj<AAllocator> mm,
                                                                      StringTable * stbl);
 
+            /** create primitive: report gc location of a value **/
+            static DPrimitive_gco_1_gco * make_gc_location_of_pm(obj<AAllocator> mm,
+                                                                 StringTable * stbl);
+
             /** create primitive: request collection **/
             static DPrimitive_gco_1_gco * make_request_gc_pm(obj<AAllocator> mm,
                                                              StringTable * stbl);
diff --git a/src/procedure2/GcPrimitives.cpp b/src/procedure2/GcPrimitives.cpp
index 76570fa..f693bd0 100644
--- a/src/procedure2/GcPrimitives.cpp
+++ b/src/procedure2/GcPrimitives.cpp
@@ -58,7 +58,6 @@ namespace xo {
                 obj<AGCObject> stats;
                 bool ok = rcx.collector().report_object_types(rcx.allocator(), rcx.error_allocator(), &stats);
 
-
                 if (ok && stats)
                     return stats;
             }
@@ -79,6 +78,33 @@ namespace xo {
 
         }
 
+        // ----- gc-location-of -----
+
+        obj<AGCObject>
+        xfer_gc_location_of(obj<ARuntimeContext> rcx, obj<AGCObject> gco)
+        {
+            std::int32_t location_code = 0;
+
+            if (rcx.collector()) {
+                location_code = rcx.collector().locate_address(gco.data());
+            }
+
+            return DInteger::box(rcx.allocator(), location_code);
+        }
+
+        DPrimitive_gco_1_gco *
+        GcPrimitives::make_gc_location_of_pm(obj<AAllocator> mm,
+                                             StringTable * stbl)
+        {
+            (void)stbl;
+
+            auto int_ty = DAtomicType::make(mm, Metatype::t_integer());
+            auto any_ty = DAtomicType::make(mm, Metatype::t_any());
+            auto pm_ty = obj<AType,DFunctionType>(DFunctionType::_make(mm, int_ty, any_ty));
+
+            return DPrimitive_gco_1_gco::_make(mm, "gc-location-of", pm_ty, &xfer_gc_location_of);
+        }
+
         // ----- request-gc -----
 
         obj<AGCObject>
diff --git a/src/procedure2/SetupProcedure2.cpp b/src/procedure2/SetupProcedure2.cpp
index a07a6ff..44d9b3e 100644
--- a/src/procedure2/SetupProcedure2.cpp
+++ b/src/procedure2/SetupProcedure2.cpp
@@ -142,6 +142,11 @@ namespace xo {
                             GcPrimitives::make_report_gc_object_types_pm(mm, stbl),
                             flags & InstallFlags::f_generalpurpose));
 
+            ok = ok & (PrimitiveRegistry::install_aux
+                           (sink,
+                            GcPrimitives::make_gc_location_of_pm(mm, stbl),
+                            flags & InstallFlags::f_generalpurpose));
+
             ok = ok & (PrimitiveRegistry::install_aux
                            (sink,
                             GcPrimitives::make_request_gc_pm(mm, stbl),