diff --git a/lib/extensions/trf/aarch32/trf.c b/lib/extensions/trf/aarch32/trf.c
index e13b4db..321c089 100644
--- a/lib/extensions/trf/aarch32/trf.c
+++ b/lib/extensions/trf/aarch32/trf.c
@@ -16,9 +16,9 @@
 
 	/*
 	 * Allow access of trace filter control registers from
-	 * non-monitor mode
+	 * non-monitor mode.
 	 */
 	val = read_sdcr();
-	val &= ~SDCR_TTRF_BIT;
+	val &= ~(SDCR_TTRF_BIT);
 	write_sdcr(val);
 }