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Can I call Semaphore_pend() in SWI?

j-breeze
Mastermind 7560 points

Hi Champ,

I'm sorry, but I'm beginner at SYS/BIOS v6.  So, I'd like to know about the mentioned in subject.
Can I call Semaphore_pend() function in SWI?

Thanks in advance for your cooperation.

Best regards,
j-breeze

  • 0
    TI__Expert 7180 points

    Hi j-breeze,

    My understanding is, Semaphore_pend() may not be called in SWI.

    Please refer the section 3.2.3 (A Comparison of Thread Characteristics) of http://www.ti.com/lit/ug/spruex3l/spruex3l.pdf.

    The table says SWI needs to "run to completion except for preemption."

    Regards,
    Atsushi

  • 0 in reply to Yokoyama, Atsushi
    Mastermind 7560 points

    Hi Atsushi San,

    Thank for your prompt reply.  I got it.
    I  really appriciate your kindly support for beginners like me.

    Best regards,
    j-breeze

  • 0 in reply to j-breeze
    TI__Mastermind 26780 points

    j-breeze,

    One thing to add… while it is not common to do it, it is possible to call Semaphore_pend() from a Swi *if* the timeout value is zero.  This allows “polling” of the semaphore value without blocking execution of the calling thread.

    For each SYS/BIOS module there is a calling context table in the “cdoc” documentation that comes with each release.  For example, for the Semaphore module:



    These tables are very useful for clarifying which calling contexts are allowed or restricted.

    Scott