Testing of SCRs for CHERI support

[francislaus]

We currently do not support Special Capability Register (SCR) testing. When looking at the RISC-V TG draft specification, it seems SCRs are soon under the "CSR hood". Until the TG specification is ratified, what do we think is the best way to test SCRs?

[PeterRugg]

They are tested I think: https://github.com/CTSRD-CHERI/QuickCheckVEngine/blob/9fc7ec5c2790f8074dab6c77a0b2cf28f2543ced/src/QuickCheckVEngine/Templates/GenCHERI.hs#L107C3-L107C9, though implementation-defined legalisation makes it difficult to test them very thoroughly