1 files changed, 1 insertions, 1 deletions
diff --git a/Src/zsh.h b/Src/zsh.h
index 19cfe216d..3db3aa3d4 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -163,7 +163,7 @@ struct mathfunc {
  */
 #define Nularg		((char) 0x9c)
 
-#define INULL(x)	(((x) & 0xf8) == 0x98)
+#define INULL(x)	((x) >= Snull && (x) <= Nularg)
 
 /*
  * Take care to update the use of IMETA appropriately when adding