Search found 10 matches

by Prathibha Prakash
Wed Sep 04, 2019 6:28 pm
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Re: Context switch

Hi, As per the reference viewtopic.php?t=1870#p15421 "The low priority thread would perform its unlock because preempted threads are always in the ISR epilogue code that does exactly that" How is it possible for the low priority thread to perform unlock after context switch,please can you ...
by Prathibha Prakash
Fri Aug 30, 2019 8:20 am
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Re: Context switch

Thank you sir for your quick and informative response.Just one more doubt,hope I'm not bugging you In the call graph of chSchGosleepS from chibios documentation http://chibios.sourceforge.net/docs3/rt/group__scheduler.html#ga97c1c514b755a1e71caf2f19c1ccf986 chSyslockFromISR(),chSysUnlockFromISR, chS...
by Prathibha Prakash
Fri Aug 30, 2019 7:48 am
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Re: Context switch

Can you explain about the the bidirectional arrow from S'-lock to I'-locked state??
by Prathibha Prakash
Fri Aug 30, 2019 1:00 am
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Re: Context switch

Thank you sir. 1. So the bidirectional arrow from S'-locked to I'-locked state in the system state is meant for this part(preempted threads are always in the ISR epilogue code that does exactly that). 2. Consider main and idle thread.If main sleeps for some some seconds a context switch occurs and t...
by Prathibha Prakash
Thu Aug 29, 2019 6:02 pm
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Re: Context switch

Hi As per the reference http://www.chibios.com/forum/viewtopic.php?t=1870#p15421 "The low priority thread would perform its unlock because preempted threads are always in the ISR epilogue code that does exactly that" Can you point out the code which describes this for more clarification.
by Prathibha Prakash
Thu Aug 29, 2019 4:40 am
Forum: ChibiOS/RT
Topic: Context switch
Replies: 11
Views: 1819

Context switch

In _port_switch ,why we are using R0 and R1 to store and load the stack pointer(R0 and R1 are general purpose registers).
by Prathibha Prakash
Wed Aug 14, 2019 6:47 am
Forum: ChibiOS/RT
Topic: Regular interrupts in S state
Replies: 2
Views: 862

Re: Regular interrupts in S state

chSysLock();
I-class()
I-class()
I-class()
chSchRescheduleS();
chSysUnlock();

In this case if a systick timer occurs while doing reschedule (S state regular intrerrupts disabled),how to service it..interrupt may miss??
by Prathibha Prakash
Tue Aug 13, 2019 12:55 pm
Forum: ChibiOS/RT
Topic: Regular interrupts in S state
Replies: 2
Views: 862

Regular interrupts in S state

In S state regular interrupts are disabled, so if a systick timer occurs while in the S state will the interrupt be skipped or serviced later??
by Prathibha Prakash
Sun Jun 23, 2019 5:42 pm
Forum: ChibiOS/RT
Topic: Interrupt handling in S state
Replies: 3
Views: 882

Re: Interrupt handling in S state

But after context switch from main thread the pointer is at thread1 and it will start running it.Lock is taken from main so it should unlock it from main,so how to leave S-state?? main thread --> chSysLock --> Context switch(pointer at thread1 in S state) How to unlock from thread1?To unlock we need...
by Prathibha Prakash
Sat Jun 22, 2019 6:33 pm
Forum: ChibiOS/RT
Topic: Interrupt handling in S state
Replies: 3
Views: 882

Interrupt handling in S state

Hi,in the demos ChibiOS/demos/various/RT-ARMCM4-USELIB it started the main thread then it sleep for some finite seconds.So when I looked at the sequence of actions taken,I can see a context switch occured.. chThdSleep --> chSysLock() --> chThdSleepS --> chSchGoSleepTimeoutS --> chSchGoSleepS --> chS...

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