[ECOS] arm/thumb interworking for gnu arm compiler/linker

[Ian Thompson <iant at CS dot Stanford dot EDU>]

Hi,

I'm using the gnupro toolkit for arm7t that was distributed with eCos
1.3.1 to compile some code in arm mode.  What I'm hoping to do is to 
call that code from another function compiled with another arm compiler.
If this calling function is also compiled in arm mode with that 
compiler, everything works fine.  However, when I try to compile the 
calling function in thumb mode and have the processor switch from thumb
to arm mode over the function call, I run into problems -- the 
processor is still in thumb mode but trying to run arm assembly, thus 
treating each arm instruction as two thumb instructions.  So my 
question is, can I somehow force a switch into arm mode via a compiler 
or linker flag in the gnu arm compiler?  After looking at the docs on 
the website, I found the -mthumb-interwork option, but there's a note 
saying it is unsupported.  Are there any patches that have this 
functionality, or any plans to implement this later?  Or is there 
something different I should try?

Thanks in advance,
ian


-- 
-----------------------------------------
Ian Thompson            iant@palmchip.com
Firmware Engineer       tel: 408.487.9626
Palmchip Corporation    fax: 408.573.7357