diff --git a/services/std_svc/psci/psci_common.c b/services/std_svc/psci/psci_common.c
index 237cf1e95..63d847608 100644
--- a/services/std_svc/psci/psci_common.c
+++ b/services/std_svc/psci/psci_common.c
@@ -185,8 +185,8 @@ unsigned long mpidr_set_aff_inst(unsigned long mpidr,
 	aff_shift = get_afflvl_shift(aff_lvl);
 
 	/* Clear the existing affinity instance & set the new one*/
-	mpidr &= ~(MPIDR_AFFLVL_MASK << aff_shift);
-	mpidr |= aff_inst << aff_shift;
+	mpidr &= ~(((unsigned long)MPIDR_AFFLVL_MASK) << aff_shift);
+	mpidr |= ((unsigned long)aff_inst) << aff_shift;
 
 	return mpidr;
 }