Dynamic Linking of modules

Hello All,

I am to design a dynamic linker/loader on Nucleus RTOS running on ARM9.
my aim is to conserve memory by loading only the required (one or more)
modules and offload other modules.
I checked out to find that the code can be compiled position independent
using the armcc compiler. also the executable format produced by armcc is
ELF(elf32-little).
I need pointers in how to design this dynamic linker as well as the
loader.

My Work Environment
Processor  :ARM9
RTOS       :Nucleus
Tool suite :RVDS for ARM9


Thnks and Rgds
Ravikiran

On Feb 28, 3:21 am, "bujji00" <rmupp...@ati.com> wrote:
> Hello All,
>
> I am to design a dynamic linker/loader on Nucleus RTOS running on ARM9.
> my aim is to conserve memory by loading only the required (one or more)
> modules and offload other modules.
> I checked out to find that the code can be compiled position independent
> using the armcc compiler. also the executable format produced by armcc is
> ELF(elf32-little).
> I need pointers in how to design this dynamic linker as well as the
> loader.

For dynamic linking/loading,
you must first define your primary and secondary memories.
The best way is to use the SVC instruction to trap into your
RTOS monitor and load from secondary memories.
Be aware that you might not be doing RT anymore.

>
> My Work Environment
> Processor  :ARM9
> RTOS       :Nucleus
> Tool suite :RVDS for ARM9
>
> Thnks and Rgds
> Ravikiran

On Mar 1, 12:21 am, "bujji00" <rmupp...@ati.com> wrote:
> Hello All,
>
> I am to design a dynamic linker/loader on Nucleus RTOS running on ARM9.
> my aim is to conserve memory by loading only the required (one or more)
> modules and offload other modules.
> I checked out to find that the code can be compiled position independent
> using the armcc compiler. also the executable format produced by armcc is
> ELF(elf32-little).
> I need pointers in how to design this dynamic linker as well as the
> loader.
>
> My Work Environment
> Processor  :ARM9
> RTOS       :Nucleus
> Tool suite :RVDS for ARM9
>
> Thnks and Rgds
> Ravikiran

Most systems have some scheme where there is a standard header at the
front of the dynamically linked file/module with a table of pointers
to functions in the module (and maybe string or integer names to index
that table).
FreeRADIUS has a system of linking in modules that may be worth
looking at to get some ideas - check out http://wiki.freeradius.org/Modules.
Because it is open source you can grab the code and see how it is
done.

- Charles