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RETROPIE · 0.6.0

RetroPie #61: PlayStation 2 (MIPS R5900 EE + GS) + #62: Xbox 360 (PPC Xenon + Xenos) — 62 LAUNCHABLE, First HD Console

June 22, 2026 · sigil-retropie · Sigil-Docs
retropie gaming 0.6.0

Two landmark systems join the fleet: PlayStation 2 (#61, 2000) — MIPS R5900 Emotion Engine (EE) 294MHz + Graphics Synthesizer (GS) + 640×448; Xbox 360 (#62, 2005) — IBM Xenon PowerPC triple-core (3×PowerPC 5xx cores, SMT) + Xenos GPU (ATI Xenos, unified shader) + 1280×720 HD. The Xbox 360 is the first HD-capable (720p) and first multi-core console in the fleet, and the first proprietary PowerPC console since the GameCube/Wii line. 62 LAUNCHABLE systems. (sigil-retropie f65664a, 0f78790)


PlayStation 2 — system #61 (f65664a)

PlayStation 2 (system #61) — MIPS R5900 EE 294MHz + GS, 640×448 rainbow framebuffer demo
PlayStation 2 (system #61) — MIPS R5900 EE 294MHz + GS, 640×448 rainbow framebuffer demo

Core: cores/ps2.sg. uart=61 PASS. apps/ps2 (EL0), loads /roms/game.iso (PS2 ISO format).

CPU: MIPS R5900 "Emotion Engine"

The EE is a 128-bit MIPS III derivative running at 294MHz, distinguished by its SIMD "Multimedia Instructions" (128-bit MMI) and an integrated integer FPU. The Emotion Engine is not just a CPU — it integrates the entire compute cluster of the PS2 on one die:

GPU: Graphics Synthesizer

The GS is a massive fill-rate rasterizer rated at 2.4 Gpixel/s peak. Crucially, there is no vertex shader on the GS — all transform and lighting (T&L) runs on the EE's VU units. The GS receives fully transformed primitives and rasterizes them at high fill rate. It renders to its own framebuffer and outputs at 640×448 (PAL/NTSC interlaced native). ps2_render copies the GS framebuffer to the display surface.

Memory: 32MB RDRAM main + 4MB VRAM (eDRAM on GS die). The RDRAM bus was controversial for its high latency but delivers the bandwidth the EE's DMA engine needs.

Architecture note: R5900 vs PSP Allegrex

The PS2's R5900 is the second MIPS system in the fleet — the PSP Allegrex (sigil-retropie #57) was first. But these are very different MIPS implementations. The Allegrex is a 32-bit MIPS-II derivative optimized for power efficiency on a handheld. The R5900 is a custom 64-bit-wide MIPS III with 128-bit SIMD extensions and dual-issue instruction-level parallelism — considerably more aggressive, designed for peak throughput at the cost of power and die area.


Xbox 360 — system #62 (0f78790)

Xbox 360 (system #62) — IBM Xenon PPC triple-core + Xenos GPU, 1280×720 HD framebuffer demo
Xbox 360 (system #62) — IBM Xenon PPC triple-core + Xenos GPU, 1280×720 HD framebuffer demo

Core: cores/xbox360.sg. uart=62 PASS. apps/xbox360 (EL0), loads /roms/game.xex (XEX executable format).

CPU: IBM "Xenon" — triple-core PowerPC

Xenon is an IBM PowerPC 5xx-derived design with three cores, each supporting 2-way SMT — giving 6 hardware threads at 3.2GHz. Xenon is PPC Book-E derived, closer to the PPC 970 than to the G3, but uses the same PowerPC ABI. Execution is in-order with AltiVec-style VMX for SIMD, making it compatible with the same VMX instruction patterns used by the GameCube's Gekko and the Wii's Broadway (both already in the fleet).

The triple-core SMT design was Microsoft's answer to the Cell Broadband Engine in the PS3 — rather than asymmetric SPEs, Microsoft chose symmetric homogeneous cores that are easier to program with standard threading models.

GPU: ATI "Xenos" — unified shader architecture

Xenos is the first GPU with a unified shader architecture — vertex and pixel shaders share the same pool of 48 shader units, allocated dynamically by the driver based on workload. This was revolutionary for 2005 and directly influenced the Direct3D 10 and OpenGL 4 specifications. Xenos uses tile-based rendering with 10MB of eDRAM for fast resolve operations (MSAA, HDR tone mapping) without going out to the main memory bus.

Memory: 512MB GDDR3 unified — CPU and GPU share the same pool, with no dedicated VRAM. The memory controller arbitrates between Xenon's cache misses and Xenos's texture fetches.

Resolution: 1280×720 (720p HD) — the first HD-capable console in the fleet. x360_render copies the Xenos back-buffer to the 720p display framebuffer, which the compositor scales to the preview window.

PowerPC lineage note

With Xenon, the fleet's PowerPC family now spans three consoles across two decades:

GameCube (2001)
IBM 750CXe "Gekko" G3 @ 485MHz — custom G3 with paired-single FPU for 3D math. System #58.
Wii (2006)
IBM "Broadway" G3 @ 729MHz — Gekko successor, backward-compatible. System #59.
Xbox 360 (2005)
IBM "Xenon" PPC 5xx @ 3.2GHz × 3 cores, 2-way SMT — first multi-core, first HD. System #62.

The HAL seam database already covers the key PPC primitives (ppc_bat, ppc_htab, ppc_tlb, ppc_altivec/VMX) that all three PPC console lines share.


Fleet milestone: 62 LAUNCHABLE systems

The last 10 systems to join the fleet, in order:

#SystemCPUYearNotable
533DOARM601993First ARM console in fleet
55Vectrex68091982Vector display output
56Nintendo DSARM9 ARMv5TE2004First Thumb ISA in fleet
57PSPMIPS Allegrex2005First MIPS + widescreen
58GameCubePPC Gekko (IBM 750CXe)2001First G3 console
59WiiPPC Broadway2006G3 line sequel
60Nintendo 3DSARM11 MPCore2011First multi-core in fleet
61PlayStation 2MIPS R5900 EE2000128-bit MIPS SIMD
62Xbox 360PPC Xenon (3-core SMT)2005First HD + unified shader