[OE-core] [PATCH 1/3] Add ARM tune file overhaul based largely on work from Mark Hatle

[Khem Raj]

> > 
> > It was my understanding that interwork was always enabled these days.  Does
> > interworking require a thumb compatible arm core?
> 
> Not for v5 and up, since the ARM-state BX instruction always exists
> (even if it isn't capable of switching to Thumb-state), and pop {pc}
> always changes state if necessary.  The combination of these two things
> means that interworking basically comes for free and there is no benefit
> to turning it off.
> 
> But for v4T, the only instruction which is capable of a state change is
> BX, and that instruction simply doesn't exist at all in the non-T v4
> architecture.  So, if you plan to run on a v4 core you must either build
> with interworking off, or (more commonly nowadays) use the --fix-v4bx
> linker option to convert BX back to MOV during final link.

We use --fix-v4bx in oe

-- 
-Khem