diff --git a/newlib/libc/sys/rtems/include/sys/bitset.h b/newlib/libc/sys/rtems/include/sys/bitset.h
index a1fd8b316..9ff18f4f3 100644
--- a/newlib/libc/sys/rtems/include/sys/bitset.h
+++ b/newlib/libc/sys/rtems/include/sys/bitset.h
@@ -44,7 +44,7 @@
 #define	__constexpr_cond(expr)	(__builtin_constant_p((expr)) && (expr))
 
 #define	__bitset_mask(_s, n)						\
-	(1L << (__constexpr_cond(__bitset_words((_s)) == 1) ?		\
+	(1UL << (__constexpr_cond(__bitset_words((_s)) == 1) ?		\
 	    (__size_t)(n) : ((n) % _BITSET_BITS)))
 
 #define	__bitset_word(_s, n)						\