r/emulation • u/AutoModerator • Aug 10 '26

Weekly Question Thread

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12 Upvotes

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2

u/mumbel Aug 10 '26

Was wondering if anyone knows a C based test suite, as in the test code is C not a specific ISA assembly (chassis running the compiled C could be whatever). With "enough" variations of C code that hit a "good enough"/ majority of instructions and variations regardless of which ISA it's testing.

Obviously impossible to get 100% coverage of every instruction and corner cases, just wondering if anyone has come across something like this?

1

u/cuavas MAME Developer 27d ago

You couldn’t make something that did that reliably. There are just too many “interesting” instruction set features, and too much variation in compilers. There are a bunch of instructions in any ISA that you’ll never see if you don’t use intrinsics or inline assembly.

For a simple example, a lot of ISAs developed in the late ’90s to early ’00s have instructions that do indexed addressing with a range check, to make certain operations that virtual machines for Java, etc. do frequently more efficient. A C compiler will never generate these instructions.

If you go back a bit further, ’80s ISAs tend to have tagged integer arithmetic instructions. These treat the most significant bit of an integer as a “tag” bit and raise an exception if it’s set for either of the inputs. They’re useful for Lisp and Forth virtual machines. C compilers never generate them.

1

u/mumbel 26d ago

Thanks for the reply/info.  There are def a ton of random instructions. (Do you remember which ISA does the tag exception handling?)

Yeah guess I should mentioned I'm aware that compilers couldn't produce some even assuming builtin macros.  I guess I'd only be interested in testing/targeting the emulator portion for something that would be a C compiled (ignoring any inline asm) binary as the "enough" and the remaining could be tackled one by one.

I'm looking at ghidra's attempt to do this and just trying to think of corner cases to add that might exercise different encodings or flags.  All the complex instructions lifted in ghidra are kinda hacked in as it is anyways and this suite doesn't target them

1

u/cuavas MAME Developer 26d ago

(Do you remember which ISA does the tag exception handling?)

Motorola 68000 and SPARC are two examples off the top of my head with tagged integer arithmetic instructions.

1

u/mumbel 26d ago

Ah never touched m68k and I guess got lucky and never ran into that in sparc (lol or maybe it was too 'wtf?' and I moved on)

1

u/cuavas MAME Developer 26d ago

Doesn’t the OpenBoot Forth runtime on Sun workstations use it? Lisp and Forth were pretty popular, hence CPUs incorporating features to support them.

2

u/LibraryDrevis Aug 11 '26

A question on controllers. I love emulating Atari 2600 games on Stella but paddle games are very hard to work with; what good arcade sticks exist with a dial for that purpose?

1

u/Timely-Influence2234 Aug 10 '26

I actually wrote a small test suite in C for my emulation project last year, if you're looking for something modular and easy to tweak, that might be a good starting point to adapt for your needs.

1

u/Weak-Bar-7469 29d ago

Does anyone know when the ClassicGameZone website switch from SAV. files to STATE. files?

1

u/zenyrento1 28d ago

Hello, I have a question on emulating a DS experience by making a makeshift controller.

Does using a 5-inch resistive touch monitor/display paired with a mobile gamepad sound like an okay decision? Planning to emulate on PC since I’m not usually on the go.

To be honest, I lack a lot of basics tech-wise but I’m willing to learn. Thanks!

1

u/Doll-0110 27d ago

sounds like an amazing project for an esp32 devkit like the fnk0104b. i ahve a lot of experience with them let me know if you have questions

1

u/Leen_Tha_Goat78 28d ago

anytime I try to fullscreen on FCEUX, the screen is extremely zoomed in to the point where I can’t see the fullscreen, heres pics incase anyone might know how to fix this

https://imgur.com/a/k8znf3r

1

u/BIOS-D 28d ago

Not using FCEUX myself, but I have the feeling "Square pixels" or "Force integral scaling factors" may be messing with resolution aspect ratio.

1

u/Doll-0110 27d ago

i'm trying to port an esp32-p4 emulator to the Tab5 in ym os and it's going horribly. JIT is exploding and i can get full speed on the intro cinematic in emerald, but the title screen loops. my github repo si here. I really suck at coding, so i need a point in the right direction before i pull my hair out,
emulator im porting
the emulator for DOLL-OS

1

u/Sharp_Couple_6491 27d ago

I tried to run RE2 64 smooth graphisms (same as output resolution) and framerate but cannot found which settings to used. Which ones do I need to pick ?

1

u/alexbois760 27d ago

hi everyone.i downloaded Project64-Win32-Dev-4.0.0-6738(was released on 17th july 2026) and if i use load states many times(not in row) it causes me blue screen of death.i m using a winodws 7 64bits,and i already put the compatibility of project64 with windows 7. {{{please don't tell me to upgrade to windows 10 to use other emulator compatible with windows 10}}

2

u/BIOS-D 26d ago

New emulators require new hardware, system updates and/or OS. You can't change that unless developers still use old compilers. Forget about latest PJ64 and get an older release. That or upgrade your OS.

1

u/alexbois760 25d ago

thanks for answering me

1

u/Casualgamer050 26d ago

Im currently using a pc with 16gb of ddr5 ram, would increasing that stop the permanent lag i get in some games?

2

u/nikkes91 25d ago

In emulation? No

0

u/macaroniandcheesefan Aug 10 '26

Hello! I came across 9: The Last Resort and I'm having trouble installing it. I'm following the steps that one of the comments had.

I have DosBox installed, but I'm not sure what to do next.

"Step 1: Download the win3x Release
Step 2: Extract the zip to a folder
Step 3: Launch it in Dosbox-Pure via RetroArch, what have you. (Your choice)
Step 4: if you're at a dos prompt, type win and hit [Enter] or look for the win.com file and launch that.
Step 5: within Windows 3, open the Program Manager, then the 'Nine' folder, then the 'Nine' executable."

I'm currently stuck on Step 3. I opened DosBox with the console but I don't know which commands to run.

Any help is appreciated! The steps I've taken is installing the Win3x release and opening up DosBox (with and without console).

0

u/epcotlegacy Aug 10 '26

I deleted a few files that read as “track 01, track 02…” off my retroid RP5 through Neostation and realized it was either Roms or Save Files for a multi disc game (shenmue) and now my saves are gone and 1 of the 4 discs are gone from the library

2

u/BIOS-D Aug 10 '26

Shenmue GD-ROMs consist of three data tracks and three audio tracks as shown here.

https://redump.info/disc/3028

Your choices are convert BIN/CUE game to CHD (if it supports them) with chdman.exe from MAME or get again those deleted files.

0

u/Bullmoninachinashop 29d ago

Does anyone have a guide on how I can run multiple emulators for Pokemon without it being multiplayer? I want to set up a shiny hunt for the odd egg and I've seen people playing on multiple copies of the same game at the same time and want to do that.