* hash.c (ll_hash): Hashing of pointers should take into

account alignment, otherwise only values divisible by the
alignment occur. This patch takes into considerations that
val values are pointers to object descriptors in a heap which
are four words wide, and so most likely aligned to 16 byte
boundaries (32 bit systems) or 32 byte boundaries (64 bit).
We need to shift.

2 files changed, 16 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index e5573ec5..d6bf9bbc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-10-19  Kaz Kylheku  <kaz@kylheku.com>
+
+	* hash.c (ll_hash): Hashing of pointers should take into
+	account alignment, otherwise only values divisible by the
+	alignment occur. This patch takes into considerations that
+	val values are pointers to object descriptors in a heap which
+	are four words wide, and so most likely aligned to 16 byte
+	boundaries (32 bit systems) or 32 byte boundaries (64 bit).
+	We need to shift.
+
 2011-10-18  Kaz Kylheku  <kaz@kylheku.com>
 
 	Task #11425
diff --git a/hash.c b/hash.c
index ece2fa46..7dbabacd 100644
--- a/hash.c
+++ b/hash.c
@@ -102,7 +102,12 @@ static cnum ll_hash(val obj)
     return c_num(obj) & NUM_MAX;
   case SYM:
   case PKG:
-    return ((cnum) obj) & NUM_MAX;
+    switch (sizeof (mem_t *)) {
+    case 4:
+      return (((cnum) obj) & NUM_MAX) >> 4;
+    case 8: default:
+      return (((cnum) obj) & NUM_MAX) >> 5;
+    }
   case FUN:
     return ((cnum) obj->f.f.interp_fun + ll_hash(obj->f.env)) & NUM_MAX;
   case VEC: