v0.9.2-scalar

This release contains multiple functional changes, some of which have been pending for a long time. See the status of the whole Scalar Cryptography extension here

Decisions Taken:

• None

Changes:

• The aes32* and sm4* instruction encodings have been changed back to regular R-type instructions.
• The aes64ks1 rcon immediate has been renamed to rnum. See #82
• The Instruction Extensions list has been changed: the ZKb group has been renamed and split into three.
  • Zbkx - The xperm.* instructions.
  • Zbkc - The Carry-less multiply instructions
  • Zbkb - All other bitmanip instructions currently in ZKb.
  • These extensions are described in this specification, and are making their way into the Bitmanip specificaiton as well. See this pull request for more. It is expected that they will be part of the Bitmanip ratification package, and simply pointed to by the scalar cryptography extension.
• Per some preliminary recommendations from the architectural consistency review:
  • packu[w] will be dropped as it is not needed for our use case of packing bytes into words.
  • rev8.w will be dropped in favour of rev8;srai
• The Entropy source has been updated to give optional access in Supervisor mode, and making it work with the Hypervisor extension.
• The Zkt extension for data independent execution latency has been updated with a complete list of instructions.

Additions:

• None

Removals:

• The packu[w] and rev8.w instructions have been removed from their relevant extensions as unnecessary / unjustified.

Open Issues:

See the status of the open issues in the project board.