System and Method for a Processing Device with a Priority Interrupt

In accordance with an embodiment, a method of operating a processor includes operating in a first operating mode that prohibits access to a protected memory area, receiving a priority interrupt (PI) signal, operating in a second operating mode in response to receiving the PI signal, and executing a first routine by asserting a semi-privileged interrupt (SPI). Access to the protected memory area is permitted in the second operating mode, and the first routine operates in the second operating mode and is interruptible by the PI signal.