A data processing device includes an electronic processor responsive to a context signal and operable in alternative processing contexts identified by the context signal. First and second registers are connected to the electronic processor to participate in one processing context while retaining information from another processing context until a return thereto. A context switching circuit is connected to the first and second registers and operates to selectively control input and output operations of the registers to and from the electronic processor depending on the processing context. Other devices, systems and methods are also disclosed.