diff --git a/lib/system/alloc.nim b/lib/system/alloc.nim
index 1c2706120e..77025265f1 100644
--- a/lib/system/alloc.nim
+++ b/lib/system/alloc.nim
@@ -104,6 +104,8 @@ type
       zeroField: int       # 0 means cell is not used (overlaid with typ field)
                           # 1 means cell is manually managed pointer
                           # otherwise a PNimType is stored in there
+      when sizeof(int) == 4:  # 32-bit only
+        headerAlignPad: array[8, byte]  # so addr(data) ≡ 8 (mod 16)
     else:
       alignment: int
 
diff --git a/lib/system/cellsets.nim b/lib/system/cellsets.nim
index 80f0367019..07bf440753 100644
--- a/lib/system/cellsets.nim
+++ b/lib/system/cellsets.nim
@@ -48,7 +48,23 @@ when defined(gcOrc) or defined(gcArc) or defined(gcAtomicArc) or defined(gcYrc):
 
   when not declaredInScope(PageShift):
     include bitmasks
+else:
+  type
+    RefCount = int
 
+    Cell {.pure.} = object
+      refcount: RefCount  # the refcount and some flags
+      typ: PNimType
+
+      when trackAllocationSource:
+        filename: cstring
+        line: int
+      elif useCellIds:
+        id: int
+      elif defined(cpu32):
+        headerAlignPad: array[8, byte]  # so addr(data) ≡ 8 (mod 16)
+
+    PCell = ptr Cell
 
 type
   PPageDesc = ptr PageDesc
diff --git a/lib/system/mmdisp.nim b/lib/system/mmdisp.nim
index ce935ff8af..7fd61e0dc3 100644
--- a/lib/system/mmdisp.nim
+++ b/lib/system/mmdisp.nim
@@ -38,21 +38,6 @@ type
   PByte = ptr ByteArray
   PString = ptr string
 
-when not defined(nimV2):
-  type
-    RefCount = int
-
-    Cell {.pure.} = object
-      refcount: RefCount  # the refcount and some flags
-      typ: PNimType
-      when trackAllocationSource:
-        filename: cstring
-        line: int
-      when useCellIds:
-        id: int
-
-    PCell = ptr Cell
-
 when declared(IntsPerTrunk):
   discard
 else: