Matteo Concas commented on a discussion: 
https://gitlab.rtems.org/rtems/rtos/rtems/-/issues/5383#note_135694


> Is there any way to enable unaligned accesses on NOEL-V?

I think this is a design choice. I could talk with someone tomorrow to get the 
rationale behind it.

> I'm not sure how they were guaranteeing strict alignment or if they were just 
> getting lucky.

GCC 9 is a bit dated and these errors we see only arose when optimized versions 
of those functions were implemented. On older versions of Newlib the functions 
are not optimized so they only do aligned (or byte-by-byte) accesses (at least 
that's my guess). So it wasn't as much luck but more unoptimized and safer 
implementations being used.

We have been running RTEMS 6.1 on the same CPU for a bit and never encountered 
this until I tried RTEMS 7 with the newer GCC.

> Ah, and getting closer to the root of the issue, it looks like the MC and 
> MC-lite processor configurations on the [gaisler noel-v 
> page](https://www.gaisler.com/products/noel-v) that are recommended for RTEMS 
> don't have MMUs at all.

I don't think that's the problem, we are running this on a what is probably 
(I'm 99% sure) the HPP64 version of the CPU.

-- 
View it on GitLab: 
https://gitlab.rtems.org/rtems/rtos/rtems/-/issues/5383#note_135694
You're receiving this email because of your account on gitlab.rtems.org.


_______________________________________________
bugs mailing list
[email protected]
http://lists.rtems.org/mailman/listinfo/bugs

Reply via email to