thejayman77/retroDE_ps2

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thejayman77 ec82764bef 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>

2026-06-29 20:10:50 -04:00

1.1 KiB

Raw Blame History

Decision 0002: BIOS Policy

Status: Locked

Context

The project needed a firmware strategy that balanced authenticity with bring-up practicality.

Main approaches considered:

real BIOS only,
HLE-only BIOS behavior,
real BIOS with narrowly-scoped debug stubs.

Options considered

Real BIOS only.
HLE-only BIOS strategy.
Real BIOS plus narrow debug stubs.

Decision

Adopt real BIOS plus narrow debug stubs.

Policy details:

Real user-supplied BIOS images remain the primary firmware path.
Debug stubs are allowed only where they materially shorten early bring-up.
Stubs must be narrow, explicit, and temporary.

Every stub must be tracked in a decision record or equivalent design note with:

owner,
purpose,
scope boundary,
removal condition.

Consequences

The project stays anchored to real PS2 boot behavior.
Early bring-up may proceed without waiting for every subsystem to be complete.
There is a maintenance cost: stub behavior must not silently become the architecture.
The repository must never include Sony BIOS images.
The stub-module plan must call out which stubs are in play for each phase.