jpolo1224
069f8a44f3
Crash and correctness - Fix a crash when backgrounding the app mid-game: onPause flushed the Vulkan pipeline cache from the UI thread while the GS thread was creating pipelines into the same VkPipelineCache. Vulkan requires that handle to be externally synchronised, so this was a driver-level data race and crashed on Adreno and Xclipse alike. The flush now runs on the GS thread, posted via the CPU thread so it does not race the EE-owned MTGS ring. - Fix an unbounded out-of-bounds vertex read in the GSRendererHW sprite-merge paving path: the inner loop advanced i instead of j, so j stayed loop-invariant and the scan walked past m_vertex->tail. - Fix per-game settings being silently ignored: gamesettings/<serial>_<CRC>.ini loads into a higher-priority layer than anything the app writes, and saves made from the library never regenerated it, so any key already in that file overrode the user permanently. Only the category-Reset path rewrote it, which is why Reset appeared to be the only thing that worked. - Fix screen rotation: the BIOS followed the launcher rotation instead of the renderer's (it has no GameInfo, and the tier was keyed on that), and the launcher stayed locked in a game's orientation after exit because the cleanup lived only inside stop()'s vmRunLoopActive-guarded branch, which loses a race against the VM thread's own finally. Rotation tier is now an explicit flag and the cleanup runs on every terminal path. - Discard the Vulkan pipeline blob whenever the SPIR-V cache is discarded. It was validated only against the device header (vendor/device/pipelineCacheUUID), which is identical across an app update, so a SHADER_CACHE_VERSION bump kept every pipeline built from the old shaders and nothing pruned it. - Make eeRecExitRequested atomic: it was a plain bool written from the JNI thread and read on the CPU thread. - OpenGL: restore GL_PACK_ALIGNMENT after readback, add the missing memory barrier after the CAS dispatch, and initialise GLState::depth_mask to GL's actual default. - DEV9: log the GetNetAdapter default: bail and the InitNet skip. Both returned silently, so a settings mistake surfaced as missing hardware three layers away. Local Link (new) - New DEV9 backend bridging emulated PS2 Ethernet between devices over authenticated local UDP, so games with a built-in LAN / System Link mode can play together. Ported from EmuCoreX (sashkinbro) with the wire format unchanged, so peers remain compatible across both forks. - Network mode picker (Online / Host / Join), host address readout, auto-derived peer ids, generated room codes, hostname support alongside numeric IPv4, and a link to the supported-games list. Fully controller-navigable. Performance - Asynchronous hardware download mode (experimental, opt-in): non-blocking GPU->CPU readback so the EE thread no longer waits on the GS thread. Ported from EmuCoreX. Appending Asynchronous to GSHardwareDownloadMode makes the enum non-ordered, so the relational comparisons on it are replaced with IsHardwareDownloadReadbackEnabled / IsHardwareDownloadEEThreadRead. - Affinity Control Mode (experimental, opt-in): EE/VU/GS priority orders plus a Performance Cores mode. Android otherwise leaves these threads unpinned. - Raise the texture-replacement cache ceiling from 6 to 16 GB; RAM/2 remains the real limiter, so this only binds at 12 GB RAM and up. - Low Latency frame pacing is no longer the default, with a one-time migration for installs that took the earlier flip. Features - Auto renderer resolves to Vulkan HW on Adreno. - Auto Progressive Scan (per-game): holds Triangle+Cross through boot. - OLED black as a modifier over any accent colour, including Custom and RGB. - Optional system keyboard instead of the built-in on-screen one. Game compatibility - Everybody's Golf 4 / Hot Shots Golf Fore! hwDownloadMode across all regions (PR #421, XDarkFallenX). - Delta Force: Black Hawk Down (PR #401, XDarkFallenX). - Reduced input latency and input handling improvements (PR #403, Splaser). RetroAchievements - Inject the client version from a build-time secret kept out of public source, with a stock-PCSX2 fallback for secret-less builds, so third parties cannot copy the client identity. Covers the iOS token too.
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