diff --git a/sys/dev/exca/exca.c b/sys/dev/exca/exca.c
index f90a3e79d97..ed39ddc3d7f 100644
--- a/sys/dev/exca/exca.c
+++ b/sys/dev/exca/exca.c
@@ -257,7 +257,7 @@ exca_mem_map(struct exca_softc *sc, int kind, struct resource *res)
 	if (win >= EXCA_MEM_WINS)
 		return (ENOSPC);
 	if (sc->flags & EXCA_HAS_MEMREG_WIN) {
-#ifdef _LP64
+#ifdef __LP64__
 		if (rman_get_start(res) >> (EXCA_MEMREG_WIN_SHIFT + 8) != 0) {
 			device_printf(sc->dev,
 			    "Does not support mapping above 4GB.");