This PR allows nemu to provide difftest so to perform non-aligned memory access of the hardware and make the behavior of both sides consistent for difftest.
@Ziyue-Zhang Please consider leaving the PR for the author to merge. Also, there are a lot of people on the reviewer list, and they haven't reviewe this PR. orz and Thanks a lot.
This PR allows nemu to provide difftest so to perform non-aligned memory access of the hardware and make the behavior of both sides consistent for difftest.