diff --git a/drivers/bus/isapnp/hardware.c b/drivers/bus/isapnp/hardware.c
index 105fa0d8dbb..a42598e3e6c 100644
--- a/drivers/bus/isapnp/hardware.c
+++ b/drivers/bus/isapnp/hardware.c
@@ -118,7 +118,7 @@ ReadDoubleWord(
     _In_ PUCHAR ReadDataPort,
     _In_ UCHAR Address)
 {
-    return ((ReadWord(ReadDataPort, Address) << 8) |
+    return ((ReadWord(ReadDataPort, Address) << 16) |
             (ReadWord(ReadDataPort, Address + 2)));
 }