Data processing apparatuses, methods and computer programs are disclosed. A range definition register is arranged to store a range specifier and filtering operations are performed with respect to a specified transaction by reference to the range definition register. The range definition register stores the range specifier in a format comprising a significand and an exponent, wherein a range of data identifiers is at least partially defined by the range specifier. When the specified transaction is with respect to a data identifier within the range of data identifiers, the filtering operations performed are dependent on attribute data associated with the range of data identifiers.