RTEMS 4.6 and tools

Thomas Rauscher trauscher at loytec.com
Mon Jan 19 08:49:54 UTC 2004


> -----Original Message-----
> From: Steven Johnson [mailto:sjohnson at neurizon.net] 
> Sent: Monday, January 19, 2004 8:56 AM
> To: rtems-users at rtems.com
> Subject: RTEMS 4.6 and tools
> Hi,
> Im trying to use RTEMS 4.6 currently with a target that will 
> run ARM and Thumb 
> code. This requires thumb-interworking.  Unfortunaltey the 
> libraries and gcc for 
> rtmes as built are not enabled for arm-thumb interworking.
> Is it possible, before release to have the tools rebuilt for arm with 
> --enable-interworking option, which will build all the 
> multilib libraries that 
> will allow arm and thumb code to co-exist.  As it stands, the 
> thumb libraries 
> are unusable because memcpy is an arm function in the thumb 
> library, and cant be 
> linked to from thumb code.
> Im going to re-build the tools at my end, I just thought i 
> would mention it so 
> that if the tools were going to be re-built in the future the 
> --enable-interworking option could be added to the arm target.

The best way (AFAIK) is to edit gcc/config/t-arm-elf in gcc's source
and comment in the required multilib options (e.g big/litte endian
arm/thumb, non-interwork/interwork).
This way, you get all useful combinations for libgcc.a and newlib.

memcpy.S however really needs to be patched (for interworking code
as well as big-endian code). I'm just testing the 
neccessary changes.

> BTW, has anyone tried building rtems on a arm-thumb target 
> before?  I know the 
> assembly that has to change (in RTEMS) to eliminate the 
> inline ARM code, but are 
> there any other gotchas I should be aware of.

Our company uses RTEMS 4.5 in ARM and THUMB code with enabled 

Unfortunately our ARM CPU support has been developed in parallel 
to the official one and is quite different.

However, I'd really like to have them in sync. Can anyone
give me some contact addresses of the ARM maintainer(s)?
Maybe there is a way to merge both CPU kits.

Best regards,

Thomas Rauscher
LOYTEC electronics GmbH
Stolzenthalergasse 24/3
A-1080 Wien
trauscher at loytec.com
Phone: +43-1-4020805-15
FAX:   +43-1-4020805-99

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