AT91RM9200 and RTEMS

Joel Sherrill joel.sherrill at
Thu Apr 29 13:18:06 UTC 2004

Steven Johnson wrote:

> It would be nice if the interworking versions of the libraries were also 
> built, because otherwise it is very difficult to build a mixed ARM-Thumb 
> program.  Ie, build RTEMS using THUMB, but all the assembler code in 
> RTEMS is still ARM.
> This would be the easiest, and you could move the 32 bit code to faster 
> memory (like a lot of ARM devices have internal).  But without 
> interworking, you cant link

I have not been paying a lot of attention but I recall some
recent traffic on the gcc list about internetworking.  Does anyone
know the status of it?

If someone is willing to test this, then I am willing to add the
multilibs.  This seems to be a popular configuration with ARM
users.  Long term, having a pure thumb mode would be nice though
especially since there isn't that much assembly.  But internetworking
is probably nice for other reasons.

> But this topic was covered earlier and apparently the version of GCC 
> RTEMS uses is broken for Thumb and Interworking?? (I dont know that its 
> broken for sure, its what I was told on this list.)

Do you have any idea when this got unbroken?  The development tree
is on gcc 3.3.3 with gcc 3.3.4 and gcc 3.4.0 on the near horizon.

> Steven
> Joel Sherrill wrote:
>> RTEMS already builds the C library for thumb so it should mainly be a
>> matter of providing alternate versions of the assembly language.
>> Primarily this should focus on cpu_asm.S and
>> libbsp/arm/shared/irq/irq_asm.S. It loosk to be about 300 lines
>> of assembly counting all comment lines and blanks.

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