Intermixing powerpc-eabi and powerpc-linux C code

Intermixing powerpc-eabi and powerpc-linux C code

[Ron McCall]

Hi!

Does anyone happen to know if it is possible to link
(and run) C code compiled with a powerpc-eabi targeted
gcc with C code compiled with a powerpc-linux targeted
gcc?  The resulting program would be run on a PowerPC
Linux system (ELDK 4.0).

In this case, main() would be compiled by
powerpc-linux-gcc while a test driver and all code to
be tested would be compiled by powerpc-eabi-gcc. 
Everything would be linked using powerpc-linux-gcc.  

The call from Linux-land to eabi-land would not need
to pass arguments nor return anything and nothing
would need to be shared between the two pieces of
code.

None of the powerpc-eabi code will depend on any
libraries or other external code, it will all be
completely self-contained.

Thanks!

Ron McCall

Re: Intermixing powerpc-eabi and powerpc-linux C code

[Paul Brook]

> The call from Linux-land to eabi-land would not need
> to pass arguments nor return anything and nothing
> would need to be shared between the two pieces of
> code.

So basically you can replace the whole thing with sleep(1); and noone would be 
any the wiser.

Paul

Re: Intermixing powerpc-eabi and powerpc-linux C code

[Ron McCall]

I guess I should have also mentioned that the
resultant program will be run under gdb, with a script
setting breakpoints, running, examining variables,
etc.

--- Paul Brook <paul@codesourcery.com> wrote:

> > The call from Linux-land to eabi-land would not
> need
> > to pass arguments nor return anything and nothing
> > would need to be shared between the two pieces of
> > code.
> 
> So basically you can replace the whole thing with
> sleep(1); and noone would be 
> any the wiser.
> 
> Paul
> 

Re: Intermixing powerpc-eabi and powerpc-linux C code

[Mike Stump]

On Jun 1, 2006, at 11:32 AM, Ron McCall wrote:
> Does anyone happen to know if it is possible to link
> (and run) C code compiled with a powerpc-eabi targeted
> gcc with C code compiled with a powerpc-linux targeted
> gcc?

This is a linker question, we don't do linkers here.  In particular,  
the relocs have to be compatible, if you want to do reloc  
processing.  You can use ld and resolve all the relocs and just slam  
in the bytes, but then, you're not using gcc to link per se.

Why not just try it out and see?

Re: Intermixing powerpc-eabi and powerpc-linux C code

[Ron McCall]

You make a good point about the linker aspect but I was first most
concerned about the code generation differences, if any. 

However, you are absolutely correct!  A test is in order.  I whipped up
a quick test program and was able to successfully compile, link and run
it, so it does indeed work!  Thanks!

On Thu, Jun 01, 2006 at 04:08:14PM -0700, Mike Stump wrote:
> This is a linker question, we don't do linkers here.  In particular,
> the relocs have to be compatible, if you want to do reloc  processing.
> You can use ld and resolve all the relocs and just slam  in the bytes,
> but then, you're not using gcc to link per se.
> 
> Why not just try it out and see?

RE: Intermixing powerpc-eabi and powerpc-linux C code

[Meissner, Michael]

> -----Original Message-----
> From: gcc-owner@gcc.gnu.org [mailto:gcc-owner@gcc.gnu.org] On Behalf
Of
> Ron McCall
> Sent: Thursday, June 01, 2006 2:33 PM
> To: gcc@gcc.gnu.org
> Subject: Intermixing powerpc-eabi and powerpc-linux C code
> 
> Hi!
> 
> Does anyone happen to know if it is possible to link
> (and run) C code compiled with a powerpc-eabi targeted
> gcc with C code compiled with a powerpc-linux targeted
> gcc?  The resulting program would be run on a PowerPC
> Linux system (ELDK 4.0).

When I last played with the powerpc many years ago, the main differences
between Linux and eabi was some details that you may or may not run into
(note these are from memory, so you probably need to check what the
current reality is):
1) eabi had different stack alignments than Linux;
2) eabi uses 2 small data registers (r2, r13) and Linux only 1 (r13?).
3) There are eabi relocations not officially in Linux and vice versa,
but the GNU linker should support any relocations the compiler uses.
4) eabi can be little endian, Linux is only big endian.
5) different system libraries were linked in by default. 

--
Michael Meissner
AMD, MS 83-29
90 Central Street
Boxborough, MA 01719