r/EmuDev • u/HELPMEICANTPUTUSER • 3d ago
PS1 emulator bug
Halloo I'm a 14 year old hobbyist and I'm making my own PS1 emulator
I've spent some time working on it and I've gotten to a stage where it loads SCE + SCEA,
But then on some games (specifically Tekken 3 and Fifa 2005) it just doesn't go past SCEA, gets frozen
On other games like GTA I, and Final Fantasy VII it goes past SCEA! But then it's just a dark screen
Also before a few days I had an old build where it would go into Fifa 2005 and Tekken 3 menus and stuff but then for example at the "E A SPORTS, TO THE GAME" Animation it would give me RGB stripes
And on Tekken 3 after the Namco Presents it would do the same
And then they just freeze,
Is this too specific a problem or..?
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u/rasmadrak 3d ago
It's a little vague, but I remember early emulators having trouble with those titles.
Keep at it - you'll crack it eventually! My suggestion would be to make sure all (and I mean all, well...mostly all) tests work 100%. Most issues go away by themselves ones the test passes with flying colors.
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u/HELPMEICANTPUTUSER 3d ago
Currently in tests with like 10 mb .bins its loading correctly
(100/100 tests passed, loads all vectors)
But at real games it isn't working
(Edit : I'm downloading multiple light games to test them! I currently figured out the issue, its with the CD-Rom reading)
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u/rasmadrak 3d ago
Maybe it's a sync issue with larger games then? :) Good luck either way! 🤘
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u/HELPMEICANTPUTUSER 3d ago
Yeah but I've tried a game called RPG maker, did precache and its stuck at a PC address loop, even if that's not the cause it's something with the CD-Rom definitely
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u/msthe_student 3d ago
Have you run any CPU accuracy tests?
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u/bufoaureus 3d ago
Could be anything basically. The game is in an infinite loop waiting on something to happen.
To correctly pinpoint that sort of issue you may need to build a debugger or at least log the instructions the cpu is executing and figure out where the loop is and what it is checking. Sometimes it is not clear from the assembly alone so decompiling the game executable with something like Ghidra (there is a plugin for psx executables) may help.
But I'd say in 90% cases it's either interrupts or cdrom timings. A lot of games are sensitive to those and just won't boot unless you get them right, and I don't remember Tekken and Final Fantasy being on the easy end of the scale.
If you are trying to boot first real games, start with Mortal Kombat II or Earthworm Jim. Those are tolerant if your timings are off and they will work with half of the hardware missing.
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u/HELPMEICANTPUTUSER 2d ago
Yeah there was a RAM cache problem... I think? I currently went way past that
It gets to Gran Turismo main menu now
And to Tekken 3 main menu aswell
My only problem is input isn't getting registered
Like everything is nearly perfect now! It runs games.. Some!For some games its just a dark screen (FFVII)
I'm working on it, I might even finish it today.
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u/Last_Bet_8677 3d ago
>14 year old
That’s very bad. Karl Witte already held a doctorate at your age.