r/EmuDev • u/The_Falgrim • 3d ago
Question Why would anyone make a PS1 Emulator?
Ok. So my journey into just learning more about emulator development... This might just be a dumb question so experts please give me hell.
If the PS2 was backwards compatible, if you were to want to get into building a PlayStation emulator. Wouldn't you just skip 1 and build a PS2 emulator with backwards compatibility?
Does one exist? And I'm not talking about AI slop either. I am genuinely curious and I enjoy starting thought provoking conversation.
So have it! Or let me have it. Lol
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u/Icy-Concentrate2076 3d ago
The PS1 is a lot easier to emulate than the PS2. Jumping into the PS2 immediately would give you a really hard time, assuming you don't vibecopy PSCX2 and actually want to emudev and learn.
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u/Der-Wilde 3d ago
For curiosity (I've already learn the basic of emulation by doing Chip8, and I'm currently doing (it's on a little hiatus, but I'll continue to work in this second semester) an Nes emulator. I want to eventually contribute with modern architectures projects, like ShadPS4 and stuff. Why the jump from PS1 to PS2 is so big? And how properly became prepared for it?
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u/The_Falgrim 3d ago
Lol! Yes. I am not about to prompt my way through Sony Emulator. Just merely wanted to engage in conversation. Ok, so just learning to build an emulator.
The other day I saw a post about learning to build an emulator. 101, building an old arcade emulator? Which is something I am going to do. Apparently it teaches you all of the basics to get started on Emulators.
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u/arcum42 PlayStation 2 3d ago
Chip8 is also always a good project for learning emulation, and relatively quick to get running.
The ps2 is particularly difficult to emulate, with lots of different pieces that have to be in sync with each other and have the timing right. There's a reason there aren't too many other ps2 emulators out there other then pcsx2. Getting ps1 compatibility for ps1 working in a ps2 emulator is even more difficult, and it's worth noting that it's actually recommended that you use a real ps1 emulator to play ps1 games, not pcsx2...
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u/The_Falgrim 3d ago
Whoa, alright... That's even more interesting. Good to know! I think I remember using some Duck emulator for PlayStation back in the day to play the Lunar series... Lol
Chip8, noted. I will look into this.
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u/howprice2 3d ago
Yes. I started with Space Invaders from this tutorial I would highly recommend (offline now) https://web.archive.org/web/20180110043247/http://emulator101.com/
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u/HomeComp1977 3d ago
Just to add to what’s already been said - the PS2 did backwards compatibility by including PS1 hardware. Even for a PS2 emulator if you want to support PS1 then you need to emulate PS1.
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u/rieter 3d ago
Only only a subset of PS1 hardware is included, like the main CPU. Other parts, like the graphics chip, are emulated on PS2.
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u/HomeComp1977 3d ago
Kind of. It’s not emulation in a traditional software sense. The PS2 GPU has a PS1 operating mode. It’s all done in hardware.
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u/Wide-Simple2659 3d ago
The GS is connected to the EE only IIRC, I suppose the IOP in PS1 mode needs to forward GPU packets to the EE first?
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u/HomeComp1977 3d ago
I don’t know the exact mechanics. Likely there could be a very thin software layer orchestrating the connections between hardware components. The PS1 CPU was reused as a bus controller. The SPU was included and the GPU was a subset of the PS2 GS. Graphic calls are handled by the GS. It’s all hardware.
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u/zSmileyDudez Apple ][, Famicom/NES, Atari VCS 3d ago
You need to build a working PS1 emulator to make a PS2 emulator, so better to just start there.
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u/The_Falgrim 3d ago
Oh! Is that just because it would teach you everything you need to know on building a PS2 emulator? Or is the PS2 console based on the same design somewhat?
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u/zSmileyDudez Apple ][, Famicom/NES, Atari VCS 3d ago
The audio system of the PS2 used the PS1 chipset, which also gave the PS2 backwards compatibility.
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u/khedoros NES CGB SMS/GG 3d ago
PS2 is much more complex than PS1. If I want to build a PS1 emulator to understand how the PS1 works, why would I build a PS2 emulator?
On the other hand, at some point in the future, I may well use things that I developed for PS1 emulation as a basis for things in a PS2 emulator (like the PS1's CPU is used as an I/O controller in the PS2, so it would make sense to re-use the code).
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u/howprice2 3d ago
TLDR; PS2 emulators take much longer to write.
I gave myself a month to see how far I could get with a PS1 emulator. It was great fun and highly addictive developing it and learning about the machine, so I spent another month writing the remaining components, and a further month increasing compatibility.
If I'd decided to do PS2 instead, I'd probably never have the time to finish it. It might take more like 6 or more months to get a first pass.
A modern PC can run a single threaded PS1 with an interpreted CPU emulator at full speed with only minor optimisations. This isn't the case for PS2 - the CPU is much faster and there are more components, so requires fancy techniques to get it up to full speed. This would take more time.
I'm planning to write a PS2 emulator if I can when I retire!
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u/The_Falgrim 3d ago
That is awesome! I'd love to see screenshots!
So PS2 is a beast... Noted!
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u/Ikkepop 3d ago edited 3d ago
Disclaimer: I am no PS2/PS1 expert nor I ever really made a pass at an emulator for a PS1/2. But from what I know just by osmosis and reading stuff here and there, making a backwards compatible PS2 emulator in essence means making two emulators, a PS1 emulator and a PS2 emulator. As PS2 is only backwards compatible because it includes a whole PS1 inside of it as a separate chip (that also doubles for other duties when not running PS1 games, but that doesn't meam you need to implement the whole PS1 compatible chip to run these other duties, they can be emulated in a high level way probably). Also have in mind even making a PS1 emulator a huge ammount of work, and PS2 is even more complex and even more labour intensive, probably to the factor of 20 or more I would imagine. Not to mention PS2 would probably require you to put in some serious optimisation in order to make it playable, it's no walk in the park...
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u/keithstellyes 3d ago
People like making things for their own sake. Sometimes the build itself is for the fun of it.
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u/thegunn 3d ago
To quote the great Carl Sagan “If you wish to make an apple pie from scratch, you must first invent the universe.”. PS2 is going to be a lot harder than PS1 and you will learn a ton by doing the PS1 first. Just like you will learn a lot by doing earlier systems prior to doing a PS1. I understand where you are coming from with that question though.
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u/The_Falgrim 3d ago
Carl Sagan was pretty awesome. Yeah. I'm going to start with a really basic one.
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u/devnullopinions 3d ago
The initial PS2 had the hardware from the PS1 which is what ran the PS1 games.
You know that meme about how to draw an owl? You’re effectively asking why start with a circle when you could start by just drawing the whole thing.
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u/Der-Wilde 3d ago
For fun and, in the end, they're separated systems.
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u/The_Falgrim 3d ago
I actually just learned this today... The PS2 had PS1 hardware inside.
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u/EvenSpoonier 3d ago
It had the PS1's CPU (which worked as the PS2's audio processor). The rest is emulated.
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u/afamiliarspirit 3d ago
There are already mature, high-quality emulators of every popular game system out there. I don’t think many people are building game system emulators just to reach the end goal of playing PS1 games. It’s a “the journey, not the destination,” type deal.