jpolo1224
48094495a0
Reported by SNAKEATEROP (Helio G99): after using the online cheats/patches
browser, going back to the game left the device heating severely and a game that
had held full speed no longer did. Nothing in the emulator explained it.
The scan was UNSTOPPABLE, not merely slow. PatchRepo's fetch functions were
plain blocking calls with no isActive check, no ensureActive and not even
suspend. Kotlin cancellation is cooperative, so cancelling the scope did
nothing: the work ran to completion no matter what the user did. It walks four
community repositories, each a multi-megabyte GitHub tree that is downloaded and
then regex-scanned for paths — that is the CPU the game was competing with, and
it kept going long after anyone was looking at it.
Three parts:
· PatchRepo's entry points are suspend and check for cancellation between
every repository and every file. Between SOURCES is the one that matters —
that is where the time goes.
· The scan's Job is tracked, so a second search cannot stack on the first, and
the browser cancels it in onDispose. viewModelScope alone was not enough:
the ViewModel is Activity-scoped and shared with the settings tab, so it
does not clear merely because the user went back to the game — which is
exactly the case that was reported.
· The progress text now says it takes a minute or two AND that leaving is
safe. Users assumed it had hung, and several were told to just wait; nobody
should have to sit through it to protect their device.
This does not make the scan faster. It makes it stop, which is the part that was
damaging. Caching the repository trees on disk is the fix for the duration —
they are re-downloaded and re-parsed on every cold start today — and is worth
doing next.
ARMSX2 — Native ARM64 JIT Fork of PCSX2
ARMSX2 is a free and open-source PlayStation 2 (PS2) emulator based on PCSX2. Its purpose is to emulate the PS2's hardware, using a combination of MIPS CPU Interpreters, Recompilers and a Virtual Machine which manages hardware states and PS2 system memory. This allows you to play PS2 games on your phone, PC, or gaming handheld, with many additional features and benefits.
Thank You
The ARMSX2 team is eternally indebted to the PCSX2 project it is based on. We are so fortunate to build on their 20 years of hardcore development.
About This Fork
The upstream PCSX2 project ships an ARM64 interpreter build for ARM, but its high-performance JIT recompilers (EE, IOP, VU0, VU1, and vtlb fast memory) are x86-64 only.
This fork exists to close that gap. The goal is to preserve the correctness features of 20 years of PCSX2 development, while generating the fastest native ARM performance possible.
Current status:
- ✅ EE (Emotion Engine) recompiler — integer, float, MMI, COP0/COP1/COP2, branches, load/store
- ✅ IOP (I/O Processor / R3000A) recompiler — full integer, load/store, branches, coprocessors
- ✅ VU (Vector Unit) recompiler — microVU skeleton + Upper FMAC vector ISA complete; Lower ISA and runtime complete
- ✅ vtlb fast memory
- ✅ Native ARM64 binary builds and boots the PS2 BIOS
- ✅ 2D games are already playable
- ✅ 3D games run
Why LLMs / AI Were Used
A word on methodology:
The x86-64 JIT code in upstream ARMSX2 is already proven correct — it has run thousands of PS2 titles for years. The challenge in this port is not emulator design or JIT theory; it is mechanical translation of a large, well-understood x86-64 assembly codebase into equivalent ARM64 assembly (via VIXL) while preserving the exact same register-allocation contracts, block lifecycle, and recompiler semantics.
Large language models (LLMs) were used as an accelerant for this translation work — pattern-matching x86 JIT boilerplate to ARM64 equivalents, scaffolding emit routines, and keeping the porting velocity high. The JIT logic (block compiler, dispatcher, analysis passes, flag pipelines, clamping rules, Tri-Ace hacks, etc.) is taken directly from the upstream x86 implementation and validated against it. Nothing was hallucinated from scratch.
In other words: the hard engineering was done by the PCSX2 team over two decades. The hard typing — translating ~50k lines of x86 emitter code into ARM64 — is what AI helped compress.
System Requirements
ARMSX2 targets ARM64 across desktop (macOS, Windows, Linux) and mobile (Android, iOS/iPadOS), all from the single shared core. Our setup documentation page contains additional details on software and hardware requirements.
Please note that a BIOS dump from a legitimately-owned PS2 console is required to use the emulator. For more information, visit this page.
Building
Check out our github actions for the latest build recipe