State retention power gating (SRPG) is an effective strategy that is widely used to help reducing power consumption of an integrated circuit while maintaining the same levels of performance and functionality.
A processor may operate in a functional mode or in a low power mode. In the functional mode, the processor performs its primary function, such as processing or storing bits. When in the low power mode the processor is shut down but state information that is indicative of a state of the processor at the end of the functional mode preceding the entry into the low power mode should be stored.