I wonder why it is so designed.

Hi, I have a question (Connection between Rocket and RoCC).

I wonder why Rocket and RoCC are designed to send and receive only UInt type data.
An error occurs in chisel when the signal contains signed data in io.mem.resp/req.bits.data.
I do not know why I should consider this when sending data.

Is there any advice, document or paper on casting operation in this case ?

Start by locating the Rocket–RoCC interface definitions associated with io.mem.resp/req.bits.data and review how Chisel represents UInt and signed signals there. Consult the Chisel casting guidance and the relevant Rocket/RoCC interface context. Done means documenting why UInt is required and how signed data should be cast or handled.

Written by the indexing model from the issue text.