[oe] [PATCH][v3 3/4] uClibc: redo configuration

[Khem Raj]

On Thu, Jul 8, 2010 at 2:34 PM, Phil Blundell <philb at gnu.org> wrote:
> On Thu, 2010-07-08 at 14:31 -0700, Khem Raj wrote:
>> On Thu, Jul 8, 2010 at 2:29 PM, Phil Blundell <philb at gnu.org> wrote:
>> > On Thu, 2010-07-08 at 14:03 -0700, Khem Raj wrote:
>> >> If I am not wrong you can still do interworking and not have bx (using
>> >> mov pc,lr)
>> >
>> > That's not an interworking instruction in ARMv4T, and I don't think it
>> > is in ARMv5TE either.  You might be thinking of pop {pc}, which is
>> > interworking in ARMv5TE, but even this is not interworking in v4t.
>>
>> tst lr, #1
>> moveq pc, lr
>> bx lr
>>
>> Thats how its done on armv4 for EABI
>
> Right, but the MOV in that case is not an interworking instruction; it's
> just a way to avoid executing BX when you don't actually need to switch
> mode, so that you can create a library which still works in an ARM-only
> environment.
>
> The final BX in that sequence is mandatory in order for it to actually
> function as an interworking return.

right you are. yes bx is always needed for thumb interworking. So I guess
for uclibc we can rely on THUMB_INTERWORK distro feature if set correctly.
>
> p.
>
>
>