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-rw-r--r--gc_hdrs.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/gc_hdrs.h b/gc_hdrs.h
index 2f2d1bf..60dc2ad 100644
--- a/gc_hdrs.h
+++ b/gc_hdrs.h
@@ -49,14 +49,16 @@ typedef struct bi {
hdr * index[BOTTOM_SZ];
/*
* The bottom level index contains one of three kinds of values:
- * 0 means we're not responsible for this block.
+ * 0 means we're not responsible for this block,
+ * or this is a block other than the first one in a free block.
* 1 < (long)X <= MAX_JUMP means the block starts at least
* X * HBLKSIZE bytes before the current address.
* A valid pointer points to a hdr structure. (The above can't be
* valid pointers due to the GET_MEM return convention.)
*/
struct bi * asc_link; /* All indices are linked in */
- /* ascending order. */
+ /* ascending order... */
+ struct bi * desc_link; /* ... and in descending order. */
word key; /* high order address bits. */
# ifdef HASH_TL
struct bi * hash_link; /* Hash chain link. */