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James Dansereau 0de99b4db4 fix(prng): correct MIPS64 dsll32/dsrl32 semantics in port/src/random.c (D284)

random.c's dsll32/dsrl32 helpers modelled the real MIPS64 dsll32/dsrl32
instructions as ordinary 32-bit shift-by-n operations, masked to 32
bits. Real MIPS64 dsll32/dsrl32 shift the FULL 64-bit register by
n+32 with no masking - they exist specifically to encode a 32-63 shift
amount in a 5-bit immediate field. The bug was bit-exact-looking but
wrong: it produced a deterministic, self-consistent stream that was
never the N64's actual stream, from the very first draw.

Surfaced by M-138's security/decomp-fidelity review (a forked review
agent's numeric trace + a hand trace of random.s both found the same
divergence); fix decided over disclose-as-known-issue per M-139b.

Fix: dsll32(x,n) = x << (n+32), dsrl32(x,n) = x >> (n+32), no masking.
No other line changes - every call site (randomGetNext,
randomGetNextFrom, chrObjRandomGetNext) already mirrors random.s/
chrObjRandom.s line-by-line through these two helpers plus plain <</>>
(which already matched dsll/dsrl correctly).

Verified against a standalone C reproduction outside the game (first
five draws from random.s's real initial seed diverge completely
between the buggy and corrected helpers, confirming the fix actually
changes the output stream). 242/242 clean build; full 21-level
verify.sh sweep PASS, no crashes.

This silently changes every RNG-derived sequence (loot, AI variance,
anything seeded from randomGetNext/randomGetNextFrom) from the first
draw in every build going forward. Savegames are unaffected (seed
isn't save state); existing recorded replays will diverge against a
post-fix build. Called out in v0.3.0 release notes per M-139c.

Claude-Session: https://claude.ai/code/session_01KwZViAFaXua3PKgHHjNgvi

2026-09-15 16:40:19 -04:00

fast3d

fix(render): land D266 IA4/texedge decode + D271 portal-culling fixes (M-139 R2)

2026-09-15 16:34:28 -04:00

include

Drop-in ROM: first-run sidecar conversion, no Python (issue #6 ) (#84 )

2026-09-13 23:17:29 -04:00

shim

linux-runtime: declare getenv()/realloc() for the strict-host build

2026-09-02 23:03:46 -04:00

src

fix(prng): correct MIPS64 dsll32/dsrl32 semantics in port/src/random.c (D284)

2026-09-15 16:40:19 -04:00

README.md

Prepare for public release

2026-09-01 19:28:59 -04:00

README.md

GoldenEye 007 — PC port layer

This directory contains the PC port layer: the code that lets the (unmodified) GoldenEye game sources run on a modern host instead of N64 hardware.

It mirrors the layout of the Perfect Dark PC port, which ports the same Rare engine family. See docs/internals.md (repo root) for the full research write-up and phased plan.

Layout

port/
├── fast3d/            # Software RSP: interprets GBI display lists -> OpenGL
│   ├── gfx_pc.cpp     #   RSP interpreter (matrices, lights, tris, fog)
│   ├── gfx_opengl.cpp #   OpenGL rendering backend (shaders, textures, zbuf)
│   ├── gfx_sdl2.cpp   #   SDL2 window-manager backend
│   ├── gfx_cc.cpp     #   color-combiner -> GLSL shader compiler
│   └── ...
├── include/           # port-facing headers
│   ├── audio.h  config.h  fs.h  input.h  mixer.h
│   ├── platform.h  romdata.h  system.h  video.h  utils.h
│   └── versioninfo.h.in
└── src/
    ├── main.c         # PC entry point (replaces boot.s / init())
    ├── libultra.c     # shims for the libultra OS API
    ├── video.c        # SDL2 window + GL context + frame pacing
    ├── audio.c        # SDL audio device, buffer queueing
    ├── mixer.c        # audio mixing
    ├── input.c        # SDL2 keyboard/mouse/gamepad -> N64 controller structs
    ├── fs.c           # filesystem abstraction over the ROM + data dir
    ├── romdata.c      # loads the .z64 ROM from disk, sets up segments
    ├── config.c       # INI config (ge007.ini)
    ├── system.c       # platform primitives (time, logging, paths)
    ├── crash.c        # crash handler / stack traces
    ├── gesched.c      # replacement RCP scheduler that drives the software RSP
    └── utils.c

How it works (short version)

The R4300 game code (src/game, src) is compiled unmodified.
The RSP is emulated in software (fast3d/): it interprets the Gfx display list the game builds and emits OpenGL calls, bypassing the RDP.
The RCP scheduler (gesched.c) replaces src/sched.c's hardware task submission: instead of writing RSP registers it calls gfx_run().
libultra OS functions are shimmed in libultra.c (single-threaded, host clock, VI/PI/SI/AI mapped onto the video/audio/fs/input layers).
Saves (Memory Pak / EEPROM) are backed by files in the data dir.

GE-specific RSP work

The PD fast3d already handles G_TRI4 (GE's 4-triangle command). The new work for GE is:

G_SETTEX — GE's custom texture-bank command (include/gbi_extension.h, gsSPUseTexture). Must be added to the RSP interpreter + GL backend.
Verify GE's custom color-combiner modes (G_CC_*FADE*) and render mode (G_RM_CUSTOM_AA_ZB_XLU_SURF) produce correct GLSL / GL state.

Use rsp/graphics/gmain.s (the real GE RSP ucode) as the ground truth for the exact command encodings.

Status

Scaffolding only. The files in src/ and fast3d/ are stubs that define the interfaces and mark the work to be done. The actual implementation is brought in phase by phase (see docs/internals.md §8), largely by adapting the PD port's port/ layer.