nios2 and atomic operations

[Joel Sherrill]

On 4/20/2015 2:18 PM, Sebastian Huber wrote:
> ----- Joel Sherrill <joel.sherrill at oarcorp.com> schrieb:
>> Hi
>>
>> As I mentioned earlier, nios2 does not link C++ iostream because of an
>> undefined reference:
>>
>> /users/joel/rtems-4.11-work/tools/lib/gcc/nios2-rtems4.11/4.9.2/libstdc++.a(locale-inst.o):/users/joel/rtems-4.11-work/rtems-source-builder/rtems/build/nios2-rtems4.11-gcc-4.9.2-newlib-2.2.0.20150323-x86_64-linux-gnu-1/build/nios2-rtems4.11/libstdc++-v3/include/ext/atomicity.h:49:
>> more undefined references to `__sync_fetch_and_add_4' follow
>>
>> I don't see anything obviously different about this target. Can someone
>> take a look at this please? It has to be something small.
> I guess Nios II lacks support for atomic operations, so the operating system must provide them in terms of helper functions.  Maybe we need a port of libatomic for this target.  It looks like something bigger.
>
That's what I was coming to believe. But why don't see this on other
targets?
I don't see how libatomic would be broken for just Nios2. We don't have
RTEMS
specific configuration in it and it only has a few ports.

What do you mean by "It looks like something bigger"?

--joel