diff --git a/sys/pc98/pc98/lpt.c b/sys/pc98/pc98/lpt.c
index f9f1c133beba..c1c9b60255e5 100644
--- a/sys/pc98/pc98/lpt.c
+++ b/sys/pc98/pc98/lpt.c
@@ -46,7 +46,7 @@
  * SUCH DAMAGE.
  *
  *	from: unknown origin, 386BSD 0.1
- *	$Id: lpt.c,v 1.16 1998/01/08 23:42:13 eivind Exp $
+ *	$Id: lpt.c,v 1.17 1998/01/24 02:54:38 eivind Exp $
  */
 
 /*
@@ -389,8 +389,14 @@ lptprobe(struct isa_device *dvp)
 	int		port;
 	static short	next_bios_lpt = 0;
 	int		status;
-	u_char		data;
-	u_char		mask;
+	static u_char	testbyte[18] = {
+		0x55,			/* alternating zeros */
+		0xaa,			/* alternating ones */
+		0xfe, 0xfd, 0xfb, 0xf7,
+		0xef, 0xdf, 0xbf, 0x7f,	/* walking zero */
+		0x01, 0x02, 0x04, 0x08,
+		0x10, 0x20, 0x40, 0x80	/* walking one */
+	};
 	int		i;
 
 	/*
@@ -413,27 +419,12 @@ lptprobe(struct isa_device *dvp)
 
 	/* Port was explicitly specified */
 	/* This allows probing of ports unknown to the BIOS */
-
 	port = dvp->id_iobase + lpt_data;
-	mask = 0xff;
-	data = 0x55;				/* Alternating zeros */
-	if (!lpt_port_test(port, data, mask))
-		{ status = 0 ; goto end_probe ; }
-
-	data = 0xaa;				/* Alternating ones */
-	if (!lpt_port_test(port, data, mask))
-		{ status = 0 ; goto end_probe ; }
-
-	for (i = 0; i < 8; i++)	{		/* Walking zero */
-		data = ~(1 << i);
-		if (!lpt_port_test(port, data, mask))
-			{ status = 0 ; goto end_probe ; }
-	}
-
-	for (i = 0; i < 8; i++)	{		/* Walking one */
-		data = (1 << i);
-		if (!lpt_port_test(port, data, mask))
-			{ status = 0 ; goto end_probe ; }
+	for (i = 0; i < 18; i++) {
+		if (!lpt_port_test(port, testbyte[i], 0xff)) {
+			status = 0;
+			goto end_probe;
+		}
 	}
 
 end_probe: