DrMIPS is a graphical simulator of the MIPS processor to support computer architecture teaching and learning. It is intuitive, versatile and configurable. The simulator is available not only for personal computers but also for Android devices, especially tablets.
DrMIPS is open-source and licensed under the GPLv3, so you are free to use, redistribute and modify it (under certain conditions).
Compiling from source
Check the INSTALL.md file for instruction on how to compile the simulator from source.
You can report bugs and ask questions at the simulator's issue tracker.
Check the CONTRIBUTING.md file for info on how to contribute.