> 
> I don't think there will be many cases where we will need to call a SWI 
> directly from thumb.  Indeed the only case I can readily think of is the 
> compiler generating an IMB (for which it would be tricky to make it switch 
> into and out of ARM mode).

Of course, an even cleaner solution would be to provide weak versions of

	arm_drain_writebuf
	arm_sync_icache

(note I've dropped the '32') directly in libc, so that the compiler can 
just call the library function.

[ They have to be weak since they aren't part of posix -- maybe we should 
also provide full symbols _arm_drain_writebuf etc that the compiler can 
use as alternate entry points ]

R.