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<a href="https://gitlab.rtems.org/matteo.concas">Matteo Concas</a>
commented on a
<a href="https://gitlab.rtems.org/rtems/rtos/rtems/-/issues/5383#note_135694">discussion</a>:
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<p style="color: inherit; line-height: 1.5; margin: 0;">Is there any way to enable unaligned accesses on NOEL-V?</p>
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<p dir="auto" style="color: #3a383f; margin: 0 0 1rem;" align="initial">I think this is a design choice. I could talk with someone tomorrow to get the rationale behind it.</p>
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<p style="color: inherit; line-height: 1.5; margin: 0;">I'm not sure how they were guaranteeing strict alignment or if they were just getting lucky.</p>
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<p dir="auto" style="color: #3a383f; margin: 0 0 1rem;" align="initial">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.</p>
<p dir="auto" style="color: #3a383f; margin: 0 0 1rem;" align="initial">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.</p>
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<p style="color: inherit; line-height: 1.5; margin: 0;">Ah, and getting closer to the root of the issue, it looks like the MC and MC-lite processor configurations on the <a href="https://www.gaisler.com/products/noel-v" rel="nofollow noreferrer noopener" target="_blank" style="margin-top: 0;">gaisler noel-v page</a> that are recommended for RTEMS don't have MMUs at all.</p>
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<p dir="auto" style="color: #3a383f; margin: 0;" align="initial">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.</p>
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