Swis can be scheduled for execution

Swis can be scheduled for execution with a call to Swi_andn(), Swi_dec(), Swi_inc(), Swi_or(), and
Swi_post(). These calls can be used virtually anywhere in the program—Hwi functions, Clock functions,
Idle functions, or other Swi functions.
When a Swi is posted, the Swi manager adds it to a list of posted Swis that are pending execution. The
Swi manager checks whether Swis are currently enabled. If they are not, as is the case inside a Hwi
function, the Swi manager returns control to the current thread.
If Swis are enabled, the Swi manager checks the priority of the posted Swi object against the priority of
the thread that is currently running. If the thread currently running is the background Idle Loop, a Task,
or a lower priority Swi, the Swi manager removes the Swi from the list of posted Swi objects and switches
the CPU control from the current thread to start execution of the posted Swi function.
If the thread currently running is a Swi of the same or higher priority, the Swi manager returns control to
the current thread, and the posted Swi function runs after all other Swis of higher priority or the same
priority that were previously posted finish execution.
When multiple Swis of the same priority level have been posted, their respective Swi functions are
executed in the order the Swis were posted.