diff --git a/heap.c b/heap.c
index 6d0edc1..820f4ac 100644
--- a/heap.c
+++ b/heap.c
@@ -3,7 +3,7 @@
 
 static mblock_t* mblock_get_next(mblock_t* block)
 {
-    return (mblock_t*)((u8*)block+(block->size & ~7));
+    return (mblock_t*)((u8*)block+MBLOCK_ALIGN_SIZE(block->size));
 }
 
 static mblock_t* mblock_by_data(void* data)
@@ -13,7 +13,7 @@ static mblock_t* mblock_by_data(void* data)
 
 static u64 mblock_get_size(mblock_t* block)
 {
-    return block->size & ~7;
+    return MBLOCK_ALIGN_SIZE(block->size);
 }
 
 void heap_init(mheap_t* heap, void* data, uword size)
@@ -40,7 +40,7 @@ void heap_join(mblock_t* start, int dir)
     if(dir > 0)
     {
         start->next = cur;
-        start->size = blk_size & ~7;
+        start->size = MBLOCK_ALIGN_SIZE(blk_size);
         if(cur)
         {
             if(cur->next) cur->next->prev = start;
@@ -51,7 +51,7 @@ void heap_join(mblock_t* start, int dir)
         if(cur)
         {
             cur = cur->next;
-            cur->size = blk_size & ~7;
+            cur->size = MBLOCK_ALIGN_SIZE(blk_size);
             cur->next = start->next;
         }
     }
@@ -70,7 +70,7 @@ void heap_split(mblock_t* block, size_t req_size)
     split->next = block->next;
     block->next = split;
     
-    split->size = (tot_size-req_size) & ~7;
+    split->size = MBLOCK_ALIGN_SIZE(tot_size-req_size);
 }
 
 void* heap_alloc(mheap_t* heap, size_t size)
diff --git a/heap.h b/heap.h
index 1bb3f7d..2d2b859 100644
--- a/heap.h
+++ b/heap.h
@@ -16,6 +16,8 @@ typedef struct {
 } mheap_t;
 
 #define MBLOCK_SIZE             (CU_WORD_SIZE*3)
+#define MBLOCK_SIZE_MASK        ((CU_WORD_BITS/8) - 1)
+#define MBLOCK_ALIGN_SIZE(size) ((size) & ~MBLOCK_SIZE_MASK)
 #define MBLOCK_ATTR_ALLOC       (1<<0)
 #define IS_MBLOCK_ALLOC(mblock) (mblock->size & MBLOCK_ATTR_ALLOC)
 
diff --git a/test.c b/test.c
index ae6c626..b17fc68 100644
--- a/test.c
+++ b/test.c
@@ -196,7 +196,7 @@ int main()
     char str5[8] = {0};
     iword val5 = 0;
     cu_sscanf((char*)str4, "\"%s\" %d", str5, 8, &val5);
-    printf("cu_sscanf\t%s\t%u\n", str5, val5);
+    printf("cu_sscanf\t%s\t%u\n", str5, val5);*/
 
     printf("[heap]\n");
     static u8 heap_data[4096];
@@ -213,7 +213,7 @@ int main()
     printf("heap_alloc\t%p\n", m3);
     printf("heap_alloc\t%p\n", m4);
     void* m5 = heap_realloc(&heap, m4, 10);
-    printf("heap_realloc\t%p\t%p\n", m4, m5);*/
+    printf("heap_realloc\t%p\t%p\n", m4, m5);
 
     cutil_exit();
     return 0;