----- Ursprüngliche Nachricht -----
Von: Peter Bigot
Gesendet am: 19 Okt 2010 04:48:41

> I doubt there's any explicit support for it.  Position independent code is
> mostly irrelevant in embedded systems where there won't be any dynamic
> loading.  There are applications where one might replace code with overlays,
> but those can be generally be handled with fixed addresses.  I believe
> binutils has support for this, though I haven't used it myself.

Well, there IS an application where PIC is required (even if it can be solved 
using non-PIC code as well):
If you need to place functions in RAM, but don't want to place them there 
permanently (by putting them into the data segment and hoping they will be 
there untouched ever after PUC).
A prominent example is a flashing function, which is copied from flash to ram 
when needed.

For those functions, however, I'd prefer the use of (inline) assembly, which 
can be made either position-independent or explicitely written for the intended 
destination.

There is another possible usage for PIC: if you want to dynamically load code 
from a library stored in external flash. Doing so using overlay mechanisms is 
far more complex (if it is a collection of more or less complex 
and indepentent functions) than using PIC.
My own projects, however, don't have grown so much that they won't fit into 
existing flash anymore, so I never needed this so far.

JMGross



2010/10/18 Fr=E9d=E9ric Sureau <[email protected]>

> Hi all,
>
> Does MSPGCC support a way to produce position independent code ?
>
> The assembly generated using "-fPIC" argument seems to still be
> position dependent.
>
> Fred
>
>


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