SimMIPS is a simulator for the MIPS 1 ISA written in C++.

The project started as part of our second year Computer Architecture coursework as students studying Electronic and Information Engineering at Imperial College London.

Since then, we have continued to work on the project, fixing errors and adding more features.

This was a collaboration between:

github: ALGCDG

personal website: https://www.doc.ic.ac.uk/~ac11018/

github: jrpdotjpg

personal website:

To build the simulator, run the following command:

make simulator

This produces a binary file bin/mips_simulator

The simulator runs MIPS 1 binary code. To run the binary, we pass its file path as an argument.

for example, if I wished to run a file bin/binary.mips.bin, I would write the following command

bin/mips_simulator bin/binary.mips.bin

The program simulates a MIPS 1 device with simple text input ouput.

To see the full list of implemented instructions, look here

X : Execute permission R : Read permission W : Write permission

Text inputs and outputs are memory mapped with the getc and putc addresses.

The testbench is a collection of MIPS assembly and C code snippets. A bashscript file then compiles these, runs them with the simulator and compares both the expected text output and return code with a reference.

The compilation process uses mips-linux-gnu-gcc and mips-linux-gnu-as. These must both be installed to create the testbench.

Something we are particularly proud of is the memory drivers Archie wrote. This allowed us to write more advanced tests far more easily. Good learning experience.

Our professor's assessment was very possitive, and only reported 4 minor errors.

• BGEZAL - our simulator linked conditionally.
• LB - Confused Error Code, returning invalid instruction instead of invalid memory access when reading NULL address
• LBU - Confused Error Code, returning invalid instruction instead of invalid memory access when reading NULL address
• LH - Don't know yet

• Fix the minor errors
• Implement Floating Point registers and instructions
• Implement Coprocessor support
• Implement a region of memory for MMIO of Graphical output
• Audio output
• Interpreted Mode