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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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