v0.3.1

Decisions Taken:

• Include the SHA512 RV32 instructions.

Changes:

• Optimised the AES RV64 instructions.
  • The hi/lo variant instructions were not needed, since we can just use the lo variants with flipped source operands.
  • Updated spec, spike, binutils, benchmarks and example RTL as appropriate.
• Toolchain: simplify the build flow for the experimental toolchain by using the riscv-gnu-toolchain repository as a base.
  • Point the gcc and binutils submodules at their respective riscv-bitmanip branches.
• Updated the AES and SHA benchmark code to be a bit nicer.

Additions:

• SHA512 RV32 Sigma/Sum instructions. See draft spec section 5.5.2.

Removals:

• All saes64.*.hi instructions were removed as unnecessary.