Re: [arm-gnu] Toolchain gcc 4.1.1 with EABI

[Paul Brook <paul@xxxxxxxxxxxxxxxx>]

On Wednesday 07 February 2007 11:01, satpal parmar wrote:
> Hi all;
>
>   I am trying to port linux 2.6.18.2 on an ARM9 based board. For that I am
> created a new toolchain using GCC-4.1.1 with EABI support.
>
> Earlier I was using linux 2.6.11.12 with GCC 4.0.3. Now problem is I am
> getting some problems in my applications during compilation.
>
> I cannot use GCC-4.0.3. for some reasons.
>
> I just want to confirm that  set of gcc-4.1.1 (eabi) with linux kernel
> 2.6.18.2 or latest are working fine without any extra patch or any 
> specific configuration.

That should work fine.

> If yes, then what effect EABi support will have on my applications and
> kernel space drivers?

Probably none. The EABI removes some of the unusual features present in older 
ARM ABIs, so is less likely to require special hacks. In practice all the 
code that needs to know about the EABI is localised in glibc and arch 
specific kernel files, and has already been fixed.

> Do I need to change in application (code particularly related to  floating
> point)?

Probably not. Some old ARM ABIs use a strange floating point format, whereas 
the EABI uses standard IEEE floating point. Unless you're doing something 
particularly strange (manually poiking at the bits of a FP value) this won't 
effect you. Even if you are doing something strange it'll probably still work 
or be trivial to fix because the EABI uses the same FP format as pretty much 
every other modern system.


If you have assembly code that calls back into C code you have to be careful 
to preserve correct stack alignment. That's about it though.

Paul