feat(tool): add some in-hand functions

include/tools

@@ -16,3 +16,16 @@ using dark::Register;
 using dark::SyncTags;
 using dark::sync_member;
 using dark::Visitor;
+
+using dark::max_size_t;
+using dark::max_ssize_t;
+
+template <dark::concepts::bit_type _Tp>
+constexpr auto to_unsigned(const _Tp &x) {
+    return static_cast<dark::max_size_t>(x);
+}
+
+template <dark::concepts::bit_type _Tp>
+constexpr auto to_signed(const _Tp &x) {
+    return static_cast<dark::max_ssize_t>(to_unsigned(x));
+}