/* -----------------------------------------------------------------------------
- * $Id: Stable.h,v 1.2 1999/02/05 16:02:28 simonm Exp $
+ * $Id: Stable.h,v 1.14 2002/12/19 14:25:04 simonmar Exp $
*
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2000
*
- * Stable names and stable pointers
+ * Stable Pointers: A stable pointer is represented as an index into
+ * the stable pointer table in the low BITS_PER_WORD-8 bits with a
+ * weight in the upper 8 bits.
+ *
+ * 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*.
*
* ---------------------------------------------------------------------------*/
+#ifndef STABLE_H
+#define STABLE_H
+
/* -----------------------------------------------------------------------------
External C Interface
-------------------------------------------------------------------------- */
extern StgPtr deRefStablePtr(StgStablePtr stable_ptr);
extern void freeStablePtr(StgStablePtr sp);
extern StgStablePtr splitStablePtr(StgStablePtr sp);
+extern StgStablePtr getStablePtr(StgPtr p);
/* -----------------------------------------------------------------------------
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 */
+ StgPtr addr; /* Haskell object, free list, or NULL */
+ StgPtr old; /* old Haskell object, used during GC */
+ StgWord ref; /* used for reference counting */
+ StgClosure *sn_obj; /* the StableName object (or NULL) */
} 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 DLL_IMPORT_RTS snEntry *stable_ptr_table;
-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 void freeStablePtr(StgStablePtr sp);
-extern inline StgStablePtr
-splitStablePtr(StgStablePtr sp)
+#ifndef RTS_STABLE_C
+extern inline
+#endif
+StgPtr deRefStablePtr(StgStablePtr sp)
{
- /* doesn't need access to the stable pointer table */
- StgWord weight = (sp & STABLEPTR_WEIGHT_MASK) / 2;
- return (sp & ~STABLEPTR_WEIGHT_MASK) + weight;
+ ASSERT(stable_ptr_table[(StgWord)sp].ref > 0);
+ return stable_ptr_table[(StgWord)sp].addr;
}
/* No deRefStableName, because the existence of a stable name doesn't
* guarantee the existence of the object itself.
*/
+
+#endif