Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

RTL (GS rasterizer, EE core stub, platform bridge, LPDDR4B path), sim regression
(272 TBs), docs, and tooling. Copyrighted PS2 content (BIOS, game code, GS dumps,
and all dump-derived textures/traces) is excluded via .gitignore and stays local.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

references/source_log.md

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+# Source Log
+
+Research pass date: 2026-04-16
+
+This log records the main sources used to build the planning notes in this
+folder.
+
+## Hardware and low-level behavior
+
+- `ps2tek - Documentation on PS2 internals`
+  URL: https://psi-rockin.github.io/ps2tek/index.html
+  Notes: best low-level consolidated hardware reference found in this pass;
+  useful for memory map, register blocks, BIOS structure, IOP boot modules,
+  DMA channels, and subsystem inventory.
+
+- `Making a PS2 Emulator: From Bits to Pixels`
+  URL:
+  https://github.com/PSI-Rockin/DobieStation/wiki/Making-a-PS2-Emulator%3A-From-Bits-to-Pixels
+  Notes: strong practical explanation of the minimum pieces needed for first
+  visible output; especially helpful for framing memory map + DMAC + GIF + GS.
+
+## SDK, tooling, and software-visible platform shape
+
+- `ps2dev`
+  URL: https://ps2dev.github.io/
+  Notes: community entry point for PS2 homebrew development.
+
+- `ps2dev/ps2dev`
+  URL: https://github.com/ps2dev/ps2dev
+  Notes: active toolchain/build umbrella for `ps2toolchain`, `ps2sdk`,
+  `ps2sdk-ports`, and `gsKit`.
+
+- `ps2dev/ps2sdk`
+  URL: https://github.com/ps2dev/ps2sdk
+  Notes: important because it exposes the software-facing EE/IOP split and
+  offers samples and platform libraries.
+
+- `ps2dev/gsKit`
+  URL: https://github.com/ps2dev/gsKit
+  Notes: low-level GS interface library; useful for understanding software-side
+  GS initialization and DMAC usage.
+
+## Emulator projects
+
+- `PCSX2/pcsx2`
+  URL: https://github.com/PCSX2/pcsx2
+  Notes: deepest and longest-running open-source PS2 emulator in this pass.
+
+- `PCSX2 Memory.cpp`
+  URL: https://raw.githubusercontent.com/PCSX2/pcsx2/master/pcsx2/Memory.cpp
+  Notes: useful implementation-side memory summary and a signpost for how a
+  mature emulator structures host-visible EE/IOP/VU memory.
+
+- `PSI-Rockin/DobieStation`
+  URL: https://github.com/PSI-Rockin/DobieStation
+  Notes: helpful as a second emulator reference and because it publishes useful
+  implementation commentary.
+
+- `jpd002/Play-`
+  URL: https://github.com/jpd002/Play-
+  Notes: useful contrasting design point; uses a built-in HLE BIOS rather than
+  external BIOS dumps.
+
+## Search outcome note
+
+I specifically looked for credible open-source HDL / FPGA PS2 core material.
+This pass did not surface a meaningful public RTL implementation. The strongest
+public sources that appeared were emulator codebases, PS2 homebrew tooling, and
+reverse-engineering references.