diff --git a/dlls/hal/hal.c b/dlls/hal/hal.c
index 79bbfed401f..0b2e4222083 100644
--- a/dlls/hal/hal.c
+++ b/dlls/hal/hal.c
@@ -167,3 +167,8 @@ ULONG WINAPI READ_PORT_ULONG(ULONG *port)
     FIXME("(%p) stub!\n", port);
     return 0;
 }
+
+void WINAPI WRITE_PORT_ULONG(ULONG *port, ULONG value)
+{
+    FIXME("(%p %d) stub!\n", port, value);
+}
diff --git a/dlls/hal/hal.spec b/dlls/hal/hal.spec
index 071eba54d67..c21806cb0b6 100644
--- a/dlls/hal/hal.spec
+++ b/dlls/hal/hal.spec
@@ -88,5 +88,5 @@
 @ stub WRITE_PORT_BUFFER_ULONG
 @ stub WRITE_PORT_BUFFER_USHORT
 @ stub WRITE_PORT_UCHAR
-@ stub WRITE_PORT_ULONG
+@ stdcall WRITE_PORT_ULONG(ptr long)
 @ stub WRITE_PORT_USHORT