[Soft-Float] - Initial Interpreter Implementation of Ps2's floating point unit specification

[GitHubProUser67]

This Pull Request implements the first take ever on real Soft-Float support in PCSX2.

This work is a combination or several efforts and researches done prior.

Credits:

• https://www.gregorygaines.com/blog/emulating-ps2-floating-point-nums-ieee-754-diffs-part-1/

• https://github.com/assumenothing/Tommunism.SoftFloat/tree/main

• https://github.com/GitHubProUser67/MultiServer3/blob/main/BackendServices/CastleLibrary/EmotionEngine.Emulator/Ps2Float.cs

• https://github.com/Goatman13/pcsx2/tree/accurate_int_add_sub

• PCSX2 Team for their help and support in this massive journey.

This pull request should be tested with every games requiring a clamping/rounding mode/float patches (cf: GameDatabase).

Currently, this PR fixes on the interpreters:

• [BUG]: DJbox (Japan) - SCPS-15082 - 56275BE9 #5169

• Ratchet & Clank 2 - Megaturret Doesn't Work Correctly #354

• [BUG]: Tourist Trophy: License Tests are broken and not completeable, player is placed out of bounds #11507

• [BUG]: Monster Hunter games: bounce calculation inaccuracy #10519

• [BUG]: Opening demo desyncs. The Taxi 2 (SLPS-20478) #8068

• [BUG]: Pride FC - Fighting Championship | Missing text and textures in Hardware and Software render modes. #7642

• [BUG]: Jak & Daxter/Jak 3 -- Character slides on his own | Jak 2 -- Inclined Camera Drift #5257

• [BUG]: Final Fantasy X Tidus Falls Through Lift #8228

• [BUG] [REGRESSION]: Final Fantasy X Bosses Turn Invisible During Death Animation #8595

• [Feature Request]: Final Fantasy X GameDB Config #10885

• [BUG]: Driv3r - Bizarre AI (?) problem: impossible to pass "Lead On Baccus" mission (the 2nd mission) #11714

• [BUG]: Camera is static in Prince of Persia: Warrior Within menu #5070

• [BUG] World Series of Poker 2008 - Battle for the Bracelets: Broken character geometry #4546

• Meta: Games that don't like the Full fpu mode. #2245

• [BUG]: FPU rounding issues in Shadow of the Colossus (SCUS-97472) #11528

• [BUG]: Tourist Trophy: License Tests are broken and not completeable, player is placed out of bounds #11507

• [BUG]: Disney's UP TLB Miss #4760

• [BUG]: Need for Speed Undercover not loading save games properly unless they’re created within PCSX2 #9831

• Gran Turismo 4 license tests

• Mortal Combat Shaolin Monks

• Tokyo Xtreme Racer Zero (Accurate Mul/Div for the EE FPU)

Any other games using the NegDiv hack or any other FPU rounding mode.

This sets the floor for Soft-Float in PCSX2, a long awaited contribution.

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[seta-san]

Does this work on the recompilers or just interpreter?

[refractionpcsx2]

You should try reading the title.

[seta-san]

You should try reading the title.

I don’t know why my brain just skimmed over that.

[MrCK1]

I ran a bunch of tests for "Test Drive Unlimited" AI during the demo scene after sitting idle on the menu. No combination of settings/interpreters seems to have any effect on behavior. There must be something else going on

[AmandaRoseChaqueta]

I can confirm with the multiplication setting that MHG and Dos not longer have bugged bounces! (Plus the build works on linux well! [as well as running interpreter can do, of course :'D])

[Shoegzer]

Shouldn't this help with #2990 as well?

[AmandaRoseChaqueta]

Shouldn't this help with #2990 as well?

I remember seeing on the public dev channel that stuntman not longer had AI issues with this and not longer the car AI failed? it's been a while

[Blackbird88]

Tourist Trophy NTSC works now too! For the first time License Tests in it work!
Requires: EE MUL/DIV

Some of the tests still don't work however.

Works

Hangs

[Tokman5]

I tested the demo replays of Tokyo Xtreme Racer Zero (see issue #5597 ) and noticed that the car movement in interpreter mode is now closer to the movement in recompiler mode.
However, there are still slight differences between the two, and both are far from matching the console playback.

comp.mp4

[Goatman13]

Nice work!

I tested only 2 games for now. Hype Time Quest which if i remember correctly needs accurate fpu mul, and it works fine without patch.

Second game is THPS4. While here accurate VU1 add/sub fix issue which is normally fixed by VU1 rounding in database, accurate mul/div breaks game graphics. Of course, game don't need accurate VU1 mul/div to work correctly, but something seems to be off when enabled.

Accurate vu1 add/sub/sqrt:

Accurate vu1 mul/div (same place in game):

Edit: Maybe THPS4 is just passing some big float value to GS with accurate mul/div. That may not necessarily be an issue with the float operation itself.
Additionally, I tested Burnout 2 and accurate VU1 add/sub fixed issue that was previously fixed by VU1 rounding mode (white car parts).

Edit2: Freaky Flyers is fixed with accurate mul/div on VU1. Awesome! We weren't even sure if that's floating points issue until now.

[GitHubProUser67]

The Tony Hawk case is fixed, the game uses an un-documented behaviour in it's 3D engine.

The PS2 has no denormals support .... except in the Mul unit apparently.

The behaviour is now emulated properly.

[Shoegzer]

I remember seeing on the public dev channel that stuntman not longer had AI issues with this and not longer the car AI failed? it's been a while

@AmyRoxwell Can you provide a reference to this? There's no indication of it being fixed in #2990, and I assume the devs would have closed it if it were. In any event it involves pathing in Driver 3 as well.

[weirdbeardgame]

2024-11-10.14-28-32.mp4

This also affects the Fatal Frame 1 issue. Meaning this + the current GameDB patch will end up being the ultimate fix

[Goatman13]

#3200 is fixed when tested with b7f3806
Require accurate mul/div for FPU.
I didn't tested, but Krome studio games should profit from this pr too, ones that have patches in game db. Like Spyro, Star Wars, one of Transformers game.

[ghost]

This pr's EE interpreter fixes #11636 's gamedb issue.

[AmandaRoseChaqueta]

I remember seeing on the public dev channel that stuntman not longer had AI issues with this and not longer the car AI failed? it's been a while

@AmyRoxwell Can you provide a reference to this? There's no indication of it being fixed in #2990, and I assume the devs would have closed it if it were. In any event it involves pathing in Driver 3 as well.

I meant like, while using this PR, not that is has been fixed. Sorry if it was misunderstood. But if it's not mention on the PR maybe the thing it needs it's not here by this initial implementation.

[GitHubProUser67]

Driv3r seemed fine when it was tested, Stuntman NTSC is a lot better but still can "slightly" deviate.

I suspect it is once again, the interpreter rounding/clamping values somewhere.

[Shoegzer]

@AmyRoxwell Ah, I understand you now. That's great news.

@GitHubProUser67 Thanks, nice to see Driv3r is looking better. Would it make sense to list these games in your OP?

[ArtificialSufficiency]

Nice to hear of stuntman finally faring better nowadays.

[Goatman13]

Game Constantine, tested US version. On level 2 there is dumpster that we need to climb to progress in game. Recompiler get it fine with positive rounding for EE. This is currently not working with soft floats, no matter what.

Reproduction steps.

• Launch first level of game.
• Use this cheat to skip to level 2: Press select, go to the Journal Screen, and enter RIGHT, LEFT, RIGHT, LEFT, RIGHT, LEFT, SQUARE, CIRCLE, CIRCLE, SQUARE, SQUARE, SQUARE, SQUARE, CIRCLE, CIRCLE.
• Jump thru fence, kill rats, there will be now dumpster on the right side, one that do not work.

[GitHubProUser67]

I managed to fix it, but the game requires accurate soft floats on the VU0 and the EE FPU, so far I tried with booth Add/Sub and Mul/Div on EE FPU/COP2 and VU0:

Edit: Positive rounding hack-fix it because it makes the float VU0 friendly. In fact the game does some weird EE FPU->VU0 communications with high floats.

[GitHubProUser67]

Note to future tests:

The constantine case is a typical case of a hack fixing a problem that is related to what I call "float broadcasting".

A game might want to transfer a out of IEEE range float from the FPU to the VUs (and vice-versa).

When a game Database entry has a rounding mode, usually it covers a can of worms where the game requires accurate soft floats on more than one processor.

[ghost]

how do you download this and put into pcsx2?

This isn’t complete nor is it tested. If you were inclined to want to test it you need to go to the “checks” part of this pr. Choose your OS and then download from the artifacts.

Ok. I'm just not very familiar with GitHub but thanks anyway.

[Tokman5]

I tested Tokyo Xtreme Racer 0's replays (#5597) again after 5c5c4c2. All demo replays and the replays recorded on console were played perfectly!

commit5c5c4c2.mp4

(Note: I enabled some cheat codes on PCSX2, so there were some visual differences but these didn't affect car movements.)

[DanteDraconi]

Tested a few different license tests in Tourist Trophy and the player is no longer placed out of bounds
Default settings with EE recompiler disabled and only multiplication/division soft-float enabled

[kunit1]

What's the plan for this PR?

[GitHubProUser67]

I am on it, I know I am late, I will try to get back to it asap.

[Retroprogram]

Hello, any news on this PR? Will it be released now?

[GitHubProUser67]

So, I will update it fairly soon with the review points, I couldn't before because of some issues I had to fix on my server.

I will try my best to finish it for december hopefully.

[mrrguest]

In Xenosaga 3 if you run behind the chest and try to face it from behind the screen will turns black, the game and sound still work but the footstep sounds like if you are running in the forest since there is a forest in this area you can visit. The black screen issue is fixed with this PR

[terremoth]

Wooow, updates! 👏👏🚀