diff --git a/trampoline/byondapi.h b/trampoline/byondapi.h
index da64561..dbf303e 100644
--- a/trampoline/byondapi.h
+++ b/trampoline/byondapi.h
@@ -44,6 +44,8 @@
 #else
 #define DM_32BIT
 #endif
+#elif defined(__aarch64__) || defined(_M_ARM64)
+#define DM_64BIT
 #endif