@@ -1,4 +1,4 @@
-/*	$NetBSD: ioccom.h,v 1.9 2007/05/29 21:32:30 christos Exp $	*/
+/*	$NetBSD: ioccom.h,v 1.10 2009/05/19 21:59:10 christos Exp $	*/
 
 /*-
  * Copyright (c) 1982, 1986, 1990, 1993, 1994
@@ -58,8 +58,9 @@
 				/* mask for IN/OUT/VOID */
 #define	IOC_DIRMASK	(unsigned long)0xe0000000
 
-#define	_IOC(inout,group,num,len) \
-	(inout | ((len & IOCPARM_MASK) << 16) | ((group) << 8) | (num))
+#define	_IOC(inout, group, num, len) \
+    ((inout) | (((len) & IOCPARM_MASK) << IOCPARM_SHIFT) | \
+    ((group) << IOCGROUP_SHIFT) | (num))
 #define	_IO(g,n)	_IOC(IOC_VOID,	(g), (n), 0)
 #define	_IOR(g,n,t)	_IOC(IOC_OUT,	(g), (n), sizeof(t))
 #define	_IOW(g,n,t)	_IOC(IOC_IN,	(g), (n), sizeof(t))