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Question about Exception and Interrupt default VSR on MPC860
- To: <ecos-discuss at sources dot redhat dot com>
- Subject: [ECOS] Question about Exception and Interrupt default VSR on MPC860
- From: "Tony Ko" <nhko at gctsemi dot com>
- Date: Wed, 19 Sep 2001 11:11:25 +0900
hi.
I look into vectors.S in MBX860 eCos source.
now I'm confused about 2 thinngs.
first thing,
There is no "scheduler_lock & scheduler_unlock routine" in Excetpion
VSR routine(cyg_hal_default_exception_vsr).
I mean there is "scheduler_lock & scheduler_unlock routine" in
Interrupt VSR routine(cyg_hal_default_interrupt_vsr)
for scheduling after interrupt service routine finished.
(actually, scheduler_unlock routine is inside "interrupt_end" routine )
second thing,
In Interrupt VSR routine, "interrupt_end" routine is called before
"restore_state" routine is called.
It seems that scheduling can occur in "interrupt_end" routine.
( there is scheduler_unlock routine in "interrupt_end" routine)
This means context switching may occur before VSR finished.
But VSR routine is finished by processing "restore_state" routine.
thanks in advance, Tony.