PS1 Emulator

What is it?

This was my dissertation project, which was a PS1 emulator. I chose this as my dissertation as I am very passionate about the 5th generation of consoles, having written code for the PS1 before.
For this, I was wanting to explore two main things. Firstly, how do you emulate a complex system like the PS1 while maintaining code readability. Secondly, the PS1 is from the early days of 3D, so it uses a fixed function pipeline. However, modern graphics apis do not. So the question then is how do you efficiently merge the two? Because of this, I used Vulkan as the renderer, as it is essentially the modern replacement for opengl.

What went right/wrong during development?

One of the big things that went wrong during development was I had some health issues. Because of this, I was unable to work on the project for several months. Because of this, when I was able to work on it again I was under very tight deadlines. So several ideas I had planned had to be scrapped. One of these was that I wanted to explore a couple different methods of emulating CPU instructions. The first being a big switch case statement with the code for each instruction, and the second being each instruction getting its own function.
This may seem like a tiny difference, however with the number of instructions the CPU has, this can make a huge difference to code readability. There is however a potential problem. Since the second method requires a function call for each instruction, there is overhead introduced by this. While it is minimal for one instruction, the CPU runs at ~30Mhz. So this small difference could end up having a large impact on performance.
One potential solution to this would be to force the functions to be inlined. However, to my knowledge there is not a crossplatform way to do this, as the inline keyword in C++ does not force inlining.
When faced with the time limit, I went with the switch case method, as in theory it provided equal or better performance with less work required by me.

One of the big things that went well during development was research/understanding, as I was able to figure out the format of the MIPS 1 instruction set relatively quickly. While I had worked with different assembly languages before, they were all simple ones that did not use pipelining. So I am quite proud that I was able to understand delay slots and write code to check they were emulated correctly.

Another thing that went well was my learning a new graphics api. Up to this point, the most modern graphics api I had used was
Direct X 11. However, the jump from this to Vulkan/Direct X 12 is quite significant. Despite this, I was able to understand it and integrate it with my CPU emulation.

Where can I access the source code?

The source code can be found on my github account. Alternatively, you can click here to go straight to the github page.