+ * SUP: StgStablePtr used to be a synonym for StgWord, but stable pointers
+ * are guaranteed to be void* on the C-side, so we have to do some occasional
+ * casting. Size is not a matter, because StgWord is always the same size as
+ * a void*.
+ *
+ * ----------------------------------------------------------------------------*/
+
+#define STABLEPTR_WEIGHT_MASK ((StgWord)0xff << ((sizeof(StgWord)-1) * BITS_PER_BYTE))
+#define STABLEPTR_WEIGHT_SHIFT (BITS_IN(StgWord) - 8)