[ECOS] Mapping specific code to specific regions in memory

[ECOS] Mapping specific code to specific regions in memory

[Amlan Chakraborty]

Hi

I am using ECOS with ARM PID7t as the  target.

Can anyone tell me how do I place some object files
into some particular region of the memory? Also how
do I configure the heap to be in some particular
region of the memory?

I want my interrupt stack and complete interrupt handler code in the
memory with zero wait states on the arm board (i.e. SSRAM)

Regards Amlan

Re: [ECOS] Mapping specific code to specific regions in memory

[Jonathan Larmour]

Amlan Chakraborty wrote:
> 
> I am using ECOS with ARM PID7t as the  target.
> 
> Can anyone tell me how do I place some object files
> into some particular region of the memory?

You need to change your linker script. Have a look at the linker
documentation at
http://www.gnu.org/manual/ld-2.9.1/html_chapter/ld_toc.html
and in particular "Memory Layout" and "Specifying Output Sections". Some of
this is best done in the eCos memory layout tool built into the
Configuration Tool (which is Windows-only at present), but some
hand-tweaking will be required to specify the object files.

> Also how
> do I configure the heap to be in some particular
> region of the memory?

This is being worked on in a generic way right now. But for now, what you
can probably do is create a linker output section (e.g. ".heap" )in the
desired location in memory, and edit the linker script to place the input
section .heap into the output section .heap, e.g.

.heap { *(.heap) }

Finally go to language/c/libc/VERSION/src/stdlib/malloc.cxx and add the
line "" to the pool definition there, i.e.

cyg_uint8 cyg_libc_malloc_memorypool[ CYGNUM_LIBC_MALLOC_MEMPOOL_SIZE ]
       __attribute__((section(".heap")))
CYGBLD_ATTRIB_WEAK;                                                             
 
This should force this array to be placed in the section ".heap".

Jifl
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