jpolo1224
1a99ab237e
A saver that dies natively made ARMSX2 unlaunchable. The choice is a persisted pref read on the library screen -- the first screen -- so the crash repeated on every launch and Settings was never reachable to turn it off. The only escape was clearing app data, which takes memory cards and save states with it. A user lost their saves that way. Cause: gl1's state is a file-scope global holding GL object names, and gl1_init() early-returns on g.ready. Skyrocket and Lattice defer initSaver() to port_resize, so a create-then-teardown with no surface size left g_started false and their port_free returned BEFORE gl1_shutdown(); flux, plasma and solarwinds leaked it the same way when initSaver() left readyToDraw clear, since returning 0 means port_free is never called. Either way g.ready stayed set with names from a destroyed EGL context, and the next saver -- new view, new context -- drew against them. Drivers answer that with anything from a black screen to a segfault. Each port now gives gl1 back on every path out, and nativeInit calls gl1_lost() as the invariant: a new context never inherits old GL names. Contained separately, because native GL can always find a new way to die: the setting arms itself with a synchronous commit() before the render thread starts and disarms when that thread exits in an orderly way. Still armed at startup means the last run died with a saver up, so the background switches off and the user is told which one. runCatching was never going to catch a SIGSEGV. Also guards Thread.start(): it asks for a 16MB stack (Skyrocket declares a 3MB starmap as a local) and an OutOfMemoryError there is an uncaught throw on the main thread -- the same lockout with no native crash involved.
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