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RE: ecos context switch & stack usage question for Sparc platform
- From: Ottawa Guy <ottawaguy81 at yahoo dot com>
- To: amassa at san dot rr dot com
- Cc: ecos-discuss at sources dot redhat dot com
- Date: Wed, 28 Apr 2004 06:51:24 -0700 (PDT)
- Subject: [ECOS] RE: ecos context switch & stack usage question for Sparc platform
Thanks Anotony,
Ecos stack is indeed falling stack. It makes sense
now.
Are you familiar with sparc platform, do you have any
idea how I could get the program counter of every
task.
Thanks again
Ottawa
--- "amassa@san.rr.com" <amassa@san.rr.com> wrote:
>
> I think the kernel code handles the location of the
> stack pointer when the
> thread is created. The code assumes a falling
> stack.
>
> If you look in thread.inl (under
> packages/kernel/current/include) the
> member function Cyg_HardwareThread::attach_stack
> handles setting up the
> stack pointer. Line 254 sets up the falling stack.
> Unless you override
> the default function with your own.
>
> Hope this helps.
>
> --Anthony
>
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
> Question 1
> ++++++++++
> In ECOS I see the stack size grows from low
> memAddress
> to high memAddress. However in sparc platform the
> stack grows from high memAddress to lowMem address.
> I
> looked at the BSP code, I was bit confused how it is
> handled. In ECOS twothread.c example
>
> char stack[6000];
> cyg_thread threadInfo;
> cyg_thread_create(4, simple_program,
> (cyg_addrword_t)
> 0,"Thread A", (void *) stack, 4096,0, threadInfo);
>
>
> Since Sparc stack grows from high to low, should it
> be
>
> cyg_thread_create(4, simple_program,
> (cyg_addrword_t)
> 0,"Thread A", (void *) ((unsigned int)stack+6000),
> 4096,0, threadInfo);
>
>
> In our application we have been using the first
> method
> without any problem. However I want to confirm this.
>
>
>
>
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