Instruction Proposal: xc.bop.3

[ben-marshall]

New instruction which is like the existing xc.bop, but which takes 3 input registers rather than just two.

• 8-bit immediate describes the logic function to implement.
• 2 source only registers
• 1 source and destination register.

Can be encoded similarly to xc.st.w, with the immediate fields repurposed as the lut function and source/destination register.

Use cases:

• SHA2
• Theta Preparation and Chi steps of Keccak
• Bitslicing anything

[ben-marshall]

Decided to replace existing bop instruction with the new proposed one above.

Todo List:

• [x] Add encoding
• [x] Specification Document Changes
• [x] Verification / Formal Check Changes
• [x] RTL Changes
• [x] Binutils changes
  • [ ] Better parsing of the operation.