A potential second general requirement for all Priv extensions:
- The hart reset state must be fully specified and should generally be UNSPECIFIED except for any key control/status bits that need to be in a specific state. (This minimizes hardware cost and leaves probably the large majority of state to be initialized by software.)
- The reset state should also specify one of:
a) The extension is "disabled" (and most, if not all, other extension state is don't care).
b) The extension is "enabled" and any key control/status bits are initialized to specific values as necessary (with all the rest UNSPECIFIED and left to be initialized by software).