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[BUG] Mapping table for ID_AA64ISAR0_EL1 is incorrect for FEAT_SHA1 and FEAT_SHA512

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Domain
documentation

Research direction

Start at the ACLE documentation's mapping section and compare the SHA feature rows with the linked ID_AA64ISAR0_EL1 documentation. Update the mapping so each SHA feature has its correct dependent register and value, then verify the rendered table and surrounding links remain correct.

Written by the indexing model from the issue text.

Description

bug

Describe the bug

The mapping table has the following rows:

Architecture name Name Dependent feature registers
FEAT_SHA1, FEAT_SHA256 sha2 ID_AA64ISAR0_EL1.SHA2 >= 0b0001
FEAT_SHA512, FEAT_SHA3 sha3 ID_AA64ISAR0_EL1.SHA3 >= 0b0001

https://arm-software.github.io/acle/main/acle.html#mapping

But this isn't quite correct. It's true that, confusingly, FEAT_SHA1 is grouped under sha2 and FEAT_SHA512 is grouped under sha3, but their ID_AA64ISAR0_EL1 values are not grouped. Per the ID_AA64ISAR0_EL1 documentation:

  • FEAT_SHA1 is ID_AA64ISAR0_EL1.SHA1 >= 0b0001
  • FEAT_SHA512 is ID_AA64ISAR0_EL1.SHA2 >= 0b0010

https://support.arm.com/documentation/ddi0601/2026-06/AArch64-Registers/ID-AA64ISAR0-EL1--AArch64-Instruction-Set-Attribute-Register-0

I think these rows probably need to be split into four, something like:

Architecture name Name Dependent feature registers
FEAT_SHA1 sha2 ID_AA64ISAR0_EL1.SHA1 >= 0b0001
FEAT_SHA256 sha2 ID_AA64ISAR0_EL1.SHA2 >= 0b0001
FEAT_SHA512 sha3 ID_AA64ISAR0_EL1.SHA2 >= 0b0010
FEAT_SHA3 sha3 ID_AA64ISAR0_EL1.SHA3 >= 0b0001
Dominant language
Python
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Forks
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Avg merge
8d 12h
Merged PRs (30d)
2

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