diff --git a/reactos/include/asm/asm.inc b/reactos/include/asm/asm.inc
index d900634089a..710d8e38ab8 100644
--- a/reactos/include/asm/asm.inc
+++ b/reactos/include/asm/asm.inc
@@ -157,6 +157,11 @@ ljmp16 MACRO segment, offset
     DW segment
 ENDM
 
+data32 MACRO opcode:VARARG
+    DB 66h
+    opcode
+ENDM
+
 UNIMPLEMENTED MACRO name
 ENDM