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[sysvabi64] Correct FMV CPU feature bit positions - #432

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Lukacma merged 2 commits into
ARM-software:mainfrom
Lukacma:split-flagm2-fix
Oct 6, 2026
Merged

Lukacma merged 2 commits into
ARM-software:mainfrom
Lukacma:split-flagm2-fix

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@Lukacma

@Lukacma Lukacma commented Oct 2, 2026

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The CPU feature table lists FEAT_FLAGM2 at both bits 2 and 3. The duplicate shifts every subsequent documented feature by one bit, from FEAT_FP16FML through FEAT_MOPS.

Remove the duplicate at bit 3 and decrement the subsequent bit positions, preserving the existing gaps. Record the correction in the change history.

The CPU feature table lists FEAT_FLAGM2 at both bits 2 and 3. The
duplicate shifts every subsequent documented feature by one bit,
from FEAT_FP16FML through FEAT_MOPS.

Remove the duplicate at bit 3 and decrement the subsequent bit
positions, preserving the existing gaps. Record the correction in
the change history.
@Lukacma
Lukacma requested a review from smithp35 October 2, 2026 13:53
@Lukacma

Lukacma commented Oct 2, 2026

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I hope I documented the change correctly in the changelog. I am not sure what release to add it as ?

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Thanks for the update. Text changes LGTM.

Can you update the change-log as suggested, and can you mention in the description that this brings the spec in line with the implementations in GCC and Clang?

After that I can approve.

Comment thread sysvabi64/sysvabi64.rst Outdated
| | | - Document Function Multi-Versioning. |
| | | - Added chapter on Thread Local Storage (TLS) |
+------------+------------------------------+-------------------------------------------------------+
| Unreleased | | - In `Function Multi-Versioning`_, remove the |

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I suggest 2026Q3 with today's date. It is likely that the editor will sanitize the change-log dates prior to release, but getting as close as we can will help that process.

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Thanks for the update. LGTM as this makes the doc match the implementations.

Will be good to give other reviewers a chance to comment, but if there's no further traffic I suggest we merge this tomorrow (6th October)

@Lukacma
Lukacma merged commit 509aee3 into ARM-software:main Oct 6, 2026
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2 participants