diff --git a/memory.c b/memory.c
index f797d82dd1..b3051d99f5 100644
--- a/memory.c
+++ b/memory.c
@@ -582,7 +582,7 @@ static MemTxResult access_with_adjusted_size(hwaddr addr,
 
     /* FIXME: support unaligned access? */
     access_size = MAX(MIN(size, access_size_max), access_size_min);
-    access_mask = -1ULL >> (64 - access_size * 8);
+    access_mask = MAKE_64BIT_MASK(0, access_size * 8);
     if (memory_region_big_endian(mr)) {
         for (i = 0; i < size; i += access_size) {
             r |= access_fn(mr, addr + i, value, access_size,