* note that serial input is not supported currently

* It will help NEMU force IPF treat cross-page IPF correctly

* It should fix snapshot error in FORCE_RAISE_PF mode

* By default, NEMU will NOT run in disambiguate mode
* Disambiguate mode is controlled by macro in /include/isa/riscv64.h

* Normal mode does not care about microarchitectural PF
* FORCE_RAISE_PF will force NEMU to raise a PF when processor raises PF
* ENABLE_DISAMBIGUATE will automatically judge if current PF is legal

* Warning: ENABLE_DISAMBIGUATE needs to run rtl_sfence, which severely
slows down NEMU simulation

* disambiguate_exec is disabled  by default to speed up NEMU