--- /dev/null
+/* -----------------------------------------------------------------------------
+ * $Id: Stable.h,v 1.1 1999/01/26 14:04:46 simonm Exp $
+ *
+ * Stable names and stable pointers
+ *
+ * ---------------------------------------------------------------------------*/
+
+/* -----------------------------------------------------------------------------
+ External C Interface
+ -------------------------------------------------------------------------- */
+
+extern StgPtr deRefStablePtr(StgStablePtr stable_ptr);
+extern void freeStablePtr(StgStablePtr sp);
+extern StgStablePtr splitStablePtr(StgStablePtr sp);
+
+/* -----------------------------------------------------------------------------
+ PRIVATE from here.
+ -------------------------------------------------------------------------- */
+
+extern StgStablePtr getStablePtr(StgPtr p);
+
+typedef struct {
+ StgPtr addr; /* either Haskell object or free list */
+ StgWord weight; /* used for reference counting */
+ unsigned int keep; /* set by the garbage collector */
+} snEntry;
+
+extern snEntry *stable_ptr_table;
+extern snEntry *stable_ptr_free;
+
+extern unsigned int SPT_size;
+
+extern inline StgPtr
+deRefStablePtr(StgStablePtr sp)
+{
+ ASSERT(stable_ptr_table[sp & ~STABLEPTR_WEIGHT_MASK].weight > 0);
+ return stable_ptr_table[sp & ~STABLEPTR_WEIGHT_MASK].addr;
+}
+
+extern inline void
+freeStablePtr(StgStablePtr sp)
+{
+ StgWord sn = sp & ~STABLEPTR_WEIGHT_MASK;
+
+ ASSERT(sn < SPT_size
+ && stable_ptr_table[sn].addr != NULL
+ && stable_ptr_table[sn].weight > 0);
+
+ stable_ptr_table[sn].weight += (sp & STABLEPTR_WEIGHT_MASK) >> STABLEPTR_WEIGHT_SHIFT;
+}
+
+extern inline StgStablePtr
+splitStablePtr(StgStablePtr sp)
+{
+ /* doesn't need access to the stable pointer table */
+ StgWord weight = (sp & STABLEPTR_WEIGHT_MASK) / 2;
+ return (sp & ~STABLEPTR_WEIGHT_MASK) + weight;
+}
+
+/* No deRefStableName, because the existence of a stable name doesn't
+ * guarantee the existence of the object itself.
+ */