diff --git a/util.c b/util.c
index e323fb2..5650fcd 100644
--- a/util.c
+++ b/util.c
@@ -534,7 +534,7 @@ typedef struct hash_node_t {
  */
 #ifdef __x86_64__
 GMQCC_INLINE uint32_t util_hthashfunc(hash_table_t *ht, const char *key, size_t seed) {
-    const uint64_t       mix   = 0xC6A4A7935BD1E995UL;
+    const uint64_t       mix   = 0xC6A4A7935BD1E995ULL;
     const int            rot   = 47;
     size_t               size  = strlen(key);
     uint64_t             hash  = seed ^ (size - mix);