def register_name(self, register_index):
        """Retrives and returns the name of an ARM CPU register.

        Args:
          self (JLink): the ``JLink`` instance
          register_index (int): index of the register whose name to retrieve

        Returns:
          Name of the register.
        """
        result = self._dll.JLINKARM_GetRegisterName(register_index)
        return ctypes.cast(result, ctypes.c_char_p).value.decode()