Chapter 3 Introduction to MR308
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Reference Semaphore Status (ref_sem, iref_sem)
Refers the status of the target semaphore. Checks the count value and existence of the wait task for
the target semaphore.
Figure 3.30 shows example task execution control provided by the wai_sem and sig_sem service
calls.
Task
Task
Task
Task
Semaphore
Counter
wai_sem sig_sem
3 2 1 0 0x
wai_sem
wai_sem
wai_sem
WAIT state
Figure 3.30 Task Execution Control by Semaphore