SuperState

enter supervisor state with user stack

Enter supervisor mode while running on the user's stack. The user still has access to user stack variables. Be careful though, the user stack must be large enough to accommodate space for all interrupt data - this includes all possible nesting of interrupts. This function does nothing when called from supervisor state.

oldSysStack

system stack pointer; save this. It will come in handy when you return to user state. If the system is already in supervisor mode, oldSysStack is zero.

UserState(), Supervisor()