All processors in the last 15-20 years have had low-power states. Its standard fare really. dropping into low power mode in an idle loop has been standard prac

All processors in the last 15-20 years have had low-power states. Its standard fare really. dropping into low power mode in an idle loop has been standard practice for that long also. In embedded systems, the real difference is how you can schedule your application-level events to make optimal use of the low power states of both the core you're using, the other cores and on-board devices (e.g. FLASHs, ADCs, DACs, etc). This is how iOS and Android try to have an effect by managing the applications use of timers and wakeups from external devices (interrupts) so as to maximise the 'sleep' time.