[ECOS] Memory Map Urgent!

Ruchika Singh rusingh@ecs.umass.edu
Wed Dec 8 23:38:00 GMT 2004

Thanks a ton for your reply John.
I am interested in pulling out all information related to a particular thread
that might be stored in any of the sections and hence using it.
So I am wondering what logic if any...decides where thread related data would
go in these sections and where can I find it.
I am using intel xscale 80200 (arm compliant) processor and GNU .

ALso you mentioned about malloc placing data at end of .bss/.data section. Are
there any linker scripts associated with it that specify this region. Where
can i get more information about this.

Would really appreciate your inputs.

John Carter <john.carter@tait.co.nz> said:

> On Tue, 7 Dec 2004, Ruchika Singh wrote:
> > I had a doubt regarding memory map for threads. Where does the initialized/
> > uninitialized data or dynamic data associated with threads ( created using
> > cyg_thread_create) end up. What i mean to ask is that are there separate
> > rodata, bss, .data sections for threads or are they interleaved with those of
> > ecos sections itself.
> Wouldn't quite say interleaved. Probably more in whatever order that the 
> the corresponding .o and .a files get presented to the linker. (But don't 
> ever rely on such an ordering, it may depend on platform / linker version 
> etc.)
> > If I create a object using malloc call in a thread A, where is this object
> > likely to be placed. Or is it that any data associated with thread will end up
> > in its associated stack??
> Only automatic variables declared down the call tree from the thread entry 
> point end up on the stack.
> Malloc places things between __heap1 symbol at the end of the .bss/.data 
> segments and the end of the ram region. This is shared between threads.
> You can configure eCos to have some per thread data space.
> John Carter                             Phone : (64)(3) 358 6639
> Tait Electronics                        Fax   : (64)(3) 359 4632
> PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
> New Zealand
> The universe is absolutely plastered with the dashed lines exactly one
> space long.


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