* OSes). This is useful for re-scavenging pages that are
* written during a GC. */
write_protected_cleared :1,
- /* the region the page is allocated to: 0 for a free page; 1
- * for boxed objects; 2 for unboxed objects. If the page is
- * free the following slots are invalid (well the bytes_used
- * must be 0). */
+ /* 000 free
+ * 10? boxed data
+ * 11? boxed code
+ * 01? unboxed data
+ * ??1 open region
+ *
+ * If the page is free the following slots are invalid, except
+ * for the bytes_used which must be zero. */
allocated :3,
/* If this page should not be moved during a GC then this flag
* is set. It's only valid during a GC for allocated pages. */