Mismatch with Xiangshan

[fly-1011]

Describe

When I was testing Xiangshan, I found inconsistencies between nemu and Xiangshan. Specifically, when executing csrrs a3, unknown_7c2, a5 instructions and then executing special illegal instructions, the following inconsistencies will occur:

The a3 value in nemu stores the pc value 80001014 where the exception occurred, and the a3 value in Xiangshan stores the data after the execution of the csrrs a3, unknown_7c2, a5 instructions.

This is the test sample and log information：test.zip

Version Information

xiangshan:commit 95cb09ae158824d3e5212946334624a692aefd58 (HEAD -> master, origin/master, origin/HEAD)
Author: cz4e 35756813+cz4e@users.noreply.github.com
Date: Fri May 30 15:27:36 2025 +0800

ready-to-run: commit 43f227c52e54cb170a894600403ea35364551518 (HEAD, origin/master, origin/HEAD)
nemu:commit: 63dcbbf

[fly-1011]

I tried adding fence.i instruction between csrrs a3, unknown_7c2, a5 and .4byte 0x79722b63 instruction, but the following inconsistency appeared

This is the test sample and log information：test1.zip

Is this due to the test case or is there another reason for the inconsistency?

[cebarobot]

CSR 0x7c2 is an custom PMA config CSR. Please check XiangShan User Guide.