[ECOS] Re: On ecos interrupt process

[张 亮]

Hi,nickg!
    thank you very much,I think i have grasped it!
    Now,i want study linux source code and  want to modify linux kernel ,
but lack of some directions,for example,how to establish  linux debug 
enviorment?
could you help me?

thank you !

Brs/zhangliang



>From: Nick Garnett <nickg@ecoscentric.com>
>To: ÕÅ ÁÁ <johnsonest@hotmail.com>
>Subject: Re: On ecos interrupt process
>Date: 23 Sep 2002 15:18:22 +0100
>
>ÕÅ ÁÁ <johnsonest@hotmail.com> writes:
>
>Please remember to copy all messages to the ecos-discuss list.
>
> > Dear nickg,
> >    thank you for your detailed explaination!
> >    could you tell me that:
> >    1) acknowledge interrupt(2) is a must?
>
>Yes. Whether it actually does anything is dependent on the design of
>the interrupt controller.
>
> >    2) who? user's ISR or OS will call acknowledge interrupt(2)?
>
>It is the job of the user ISR to do this. It should usually do this as
>soon as it has cancelled the interrupt source in the device.
>
> >    3)if IRQ1(higher) is processing,after acknowledge
> > interrupt(2)lower interrupt will be process if any,right? so if
> > [enable interrupts](1)was called, lower interrup will post DSR
> > before higher interrupt.of course,it is accepted.
> >
>
>This depends on the design of the interrupt controller and the CPU
>architecture. If the architecture implements an IPL mechanism then
>lower priority interrupts will be pended until higher priority
>interrupts return. If there is no IPL then acknowledging a higher
>priority interrupt may allow lower priority interrupt in. It is the
>responsibility of the ISR to acknowledge at a point where this would
>be safe.
>
>DSRs are not prioritized and it is no specified what order they are
>executed in. The default is currently LIFO order.
>
>
>--
>Nick Garnett - eCos Kernel Architect
>http://www.eCosCentric.com/




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