Handoff brief — GoldenEye 007 PC port (Phase 1.5 done, Phase 2: first frames render)

Paste-ready briefing for the next agent session. The authoritative detail lives in AGENTS.md and docs/PCPortResearch.md (§H handoff, §F/D31–D44 findings); this is the summary + the immediate tasks.

Your job

Two tasks, in order:

D44 (quick win, ~15 min): one-line fix to the crash handler — DONE, committed. Every crash now auto-logs a BACKTRACE: section to stdout and ge007.crash.log; the D43 chain (#00 model.c:5688 ← #01 load_object_fill_header) was confirmed without gdb. The debug loop is now "read ge007.crash.log".
D43 (main task): model-file loading ABI mismatch — stage object load faults in modelPromoteNodeOffsetsToPointers() (src/game/model.c:5688) because ROM model files are serialized with N64 layout (4-byte pointer fields) but read on PC as 8-byte-pointer structs. Fix it with a D37-style re-layout in port/src/romdata.c, then keep pushing rendering forward (more asset types will fault the same way).

Work agentically — fix → build (~5 s) → verify → commit at each working milestone. Commit message style: PC port: <phase> — <what>.

Read first (authoritative, in order)

AGENTS.md — non-negotiables, critical files, build, verification ritual, phase status.
docs/PCPortResearch.md §H (handoff + plan), then §F/D44 (the quick win), D43 (the open model-file task), §2.4 (PD-port copy-candidate audit — read before starting D43 or Phase 3/4), D37 (the libaudio bank-tree re-layout pattern), D39–D42 for the first-render fixes, D31–D38 for background.

Non-negotiables (the ones that bite)

N64 build files (Makefile, tools/, rsp/, ld/) — never touch.
Game logic is unmodified. Hardware deps go in port/. Narrow exception: mechanical, semantics-preserving ABI/layout fixes forced by the 32→64-bit transition (embedded pointers → u32 + cast at use; PC-guarded pool sizing / idiom branches), each documented as a D3x finding. No behavior changes.
Region macros in CMakeLists.txt must mirror the N64 Makefile exactly.

Current state (verified live this session, 2026-08-22)

Re-ran the committed build: frames 1–4 render ([NOTE] frame N rendered in … us, frame 1 ~21 ms), then FATAL 0xc0000005 at PC 0x14007a31a = modelPromoteNodeOffsetsToPointers() model.c:5688 — exactly D43. The black screen you see is the clear color only: display lists execute but no stage geometry has loaded yet.
Dev loop measured (16-core box): full clean rebuild ≈ 5 s wall; launch → crash ≈ 3.7 s. Neither is a bottleneck — diagnosis is (gdb launch-only mode + manual addr2line arithmetic per fault). ccache and boot fast-forward are NOT worth it.
D44 fixed + committed: crashStackTraceSym() in port/src/crash.c calls GetCurrentThreadStackLimits(low, high) — passing NULL pointer values instead of &low, &high. The API writes to address 0x0 inside the SEH filter → the process dies before printing the backtrace. That's why ge007.crash.log contains only Phase 1 (EXCEPTION/PC/MODULE lines) and no BACKTRACE: section, and why every D3x fault so far cost a gdb session. The build already uses -fno-omit-frame-pointer (CMakeLists.txt:193), so the EBP-chain walk will work once the call is fixed.
ROM dump verified: byte-identical to the No-Intro good dump, header CRCs re-compute clean (tools_pc/romverify.c). Fingerprint + provenance in Environment below.
Frames render because of D31–D42 (all documented in §F): boot chain (real-zlib decompression, animation-table ABI+endianness, ANIM_DATA lvalues, music seq-table fixup, music-heap sizing, libaudio bank-tree re-layout), D38 prototype shim (warning-clean build), D39 Globalimagetable rebasing (GIMG_OFF() idiom), D40 ModelHitEntry pool sizing, D41 WGL single-thread context currency (gfx_sdl_release_context()), D42 rsp.c pointer-toggle truncation.

Immediate task 1 — D44 (DONE — committed)

The one-line fix (GetCurrentThreadStackLimits(&low, &high) in crashStackTraceSym()) is in. Verified: BACKTRACE: with #00 at model.c:5688 and #01 load_object_fill_header appears on stdout + in ge007.crash.log. Caveats learned: (a) frames past the true chain can be stale stack data — validate a frame's address is inside .text before trusting it; (b) addr2line wants the full absolute hex address directly (addr2line -e build-pc/ge007.x86_64.exe -f -C 0x14007a31a).

Immediate task 2 — D43: model-file loading ABI mismatch

Reproduce: run; after a few rendered frames it SIGSEGVs in modelPromoteNodeOffsetsToPointers() (model.c:5688) during stage object load via load_object_fill_header() (src/game/objecthandler_2.c:89). With D44 fixed, the crash log gives you the call chain for free.
Understand the file format from bondtypes.h (ModelFileHeader, ModelNode, ModelRoData union + per-opcode records) and bondconstants.h (MODELNODE_OPCODE_*). N64 layout: header 24 B, node 20 B, all pointers 4 bytes. Do NOT design the re-layout from scratch: PD port's port/src/preprocess/filemodel.c (1,114 lines) is a Rare-validated near-analogue — same PROMOTE idiom, same vma 0x5000000. Read it first; adapt its node walk / placement / record handling. GE's ModelRoData union + opcodes differ (PD has stargunfire/headspot/gundl types), so validate every GE record type per-field against bondtypes.h + ROM ground truth.
Implement the two-pass re-layout in port/src/romdata.c: walk the node tree (Child/Next/Parent links), place every sub-struct once (8-aligned) in a compact image, rewrite each embedded pointer as a zero-extended offset from the image start, so the existing PROMOTE rebase (diff = fileramaddr - vma, vma = 0x5000000) works unmodified. Hook it between the romCopy in load_resource() and first use (or at the load_object_fill_header call sites — choose the narrowest correct hook).
Validate one small model against ROM ground truth before generalizing (opcode sequence, node links, a few Data records). gdb works; or write the optional tools_pc/romdump.py inspector (below) and validate statically.
Expect follow-on faults in other asset types (BG/stan/propobj tables) — same procedure; note PD's preprocess/ module already solves most of them (filebg.c, filetiles.c, filepads.c, filesetup.c, …) — see the PD reference section below.

Dev-loop speedups (build these when they pay off, not before)

Priority order from the last session's measurements:

D44 (above) — automatic backtraces; biggest win per diagnosis.
tools_pc/sym.sh — tiny wrapper: takes a PC or rel offset, adds image base 0x140000000, runs addr2line -e build-pc/ge007.x86_64.exe -f -C. Kills the manual arithmetic; pairs with the crash log (one command per crash). Re-verify the image base with info address after any link-layout change.
tools_pc/romdump.py — Python ROM/asset inspector: load data/ge007.ntsc-final.z64, parse ModelFileHeader/ModelNode trees using the bondtypes.h layout, print opcode sequences / node links / Data records for a given cart address. Accelerates D43 and every follow-on asset type; validates re-layout output against ROM ground truth without running the game. (Python here: no f-strings with nested quotes — use % formatting.)
Frame capture + pixel assert — env-gated framebuffer PPM dump every N frames in port/, plus a script that counts non-clear-color pixels / diffs two captures. Turns "the scene contains actual model geometry" into an assert, makes the 30 s soak scriptable, and enables screenshot diffs against an emulator (Mupen64Plus with the verified No-Intro dump as ground truth).

PD port as standing reference (always available)

PD_PORT_CHECKOUT is the Perfect Dark PC port — same Rare engine family, and the standing reference/guidance source for this project (noted in AGENTS.md). Consult it whenever a remaining work item has a PD analogue:

Phase 2 asset conversion: port/src/preprocess/ (~4,100 lines) — per-ROM-segment N64→PC layout converters hooked from their romdata.c. filemodel.c = D43 near-analogue (same vma 0x5000000); filebg.c (expected follow-on), segaudio.c (cross-check for our D37 bank-tree fixup), filelang.c, filetiles.c, filepads.c, filesetup.c, gbi.c, segfonts.c.
Phase 3/4 (copy-and-adapt; our stubs were scaffolded for this): port/src/mixer.c (722 lines vs our 31 — libaudio→SDL mixer), input.c (1,551 vs 48 — SDL_GameController backend with hotplug/rumble/keyboard; remap buttons to GE's scheme), fs.c (294 vs 81 — file-backed save dir for Phase 4 EEPROM/PFS).
Caveats: copy port-layer files only (their game code was modified for PC); same family ≠ identical format — validate every conversion per-field against GE headers + ROM ground truth. Full audit: docs/PCPortResearch.md §2.4.

Standing procedure (you will hit more of these)

Every ROM-serialized struct with a pointer field faults the same way once you reach more asset loading. The D32 fix procedure (doc §H): at the fault, ptype /o <Struct>; if a pointer field's offset/size diverges from its N64 offset comment, change it to u32 + cast at the use sites; verify the load-time rebase yields valid V1 addresses (< 0x80000000); also check the ROM bytes' endianness per-field (D33 rule: u32 bswap32 / u16 bswap16 / u8 identity) and any fixup loop's pointer stride on x86-64; for packed struct trees use the D37 re-layout pattern; for address-arithmetic idioms over exe symbols (D39/D42 class) guard a PC branch that reproduces the N64 32-bit value exactly. Rebuild; confirm boot advances. Log each as D3x in §F and note it in AGENTS.md phase status.

Environment (do not rediscover these)

MSYS2/MinGW tools are in /c/msys64/mingw64/bin/ — not on PATH. Prefix every shell: export PATH="/c/msys64/mingw64/bin:$PATH".
Build: ./build-pc.sh ntsc-final (incremental; full rebuild only when port/shim/ changes; a clean full build is ~5 s on the 16-core dev box). ROM is at data/ge007.ntsc-final.z64 (= baserom.u.z64, byte-identical).
The ROM is mapped at cart base 0x10000000 on PC (romdataInit), so &<segment>Symbol values (e.g. _sfxctlSegmentRomStart = 0x102EBDE0) are directly dereferenceable host pointers into the ROM image; romCopy() copies from those cart addresses. All game RAM lives in the V1 view at 0x70xxxxxx (< 4 GiB) — s32 truncation of game-RAM pointers is lossless (this is why D39 needed no changes outside image_bank.c).
ROM provenance (verified 2026-08): byte-identical to the No-Intro good dump GoldenEye 007 (U) [!].z64 (kept in data/). MD5 70c525880240c1e838b8b1be35666c3b, SHA-256 2cdcec8a9f0cb6e36337f3ee39d8ad105dc8afa6ba1c02d466e8f5b771f9a162, 0xC00000 bytes, country 'E' (US). Header CRCs DCBC50D1/09FD1AA3 re-verify with tools_pc/romverify.exe.
gdb: launch mode only (gdb -batch -ex "handle SIGSEGV stop" -ex run …). Symbolicate offline with addr2line -e build-pc/ge007.x86_64.exe -f -C <0x140000000+rel>. Image base is 0x140000000 (re-verify with info address after a rebuild). Debug scripts live in build-pc/ (d37_tree.py, d39_*.gdb, d41_probe.gdb, …).
Crash log: ge007.crash.log (repo root) now holds Phase 1 + a BACKTRACE: section (D44 fixed). First stop for any fault; symbolicate with addr2line -e build-pc/ge007.x86_64.exe -f -C <abs-addr>. Frames past the true chain may be stale — sanity-check they fall inside .text.
objdump -d --disassemble=<fn> / objdump -s -j .data on build-pc/ge007.x86_64.exe is a fast way to check what the compiler actually emitted.
Many init functions use a fake RBP — compute stack offsets from the entry RSP, not RBP.
Python on this box: no f-strings with nested quotes (< 3.12) — use % formatting.

Definition of done (this milestone)

Checkpoint A: D44 committed — crash log shows a real backtrace for the D43 fault. Then the milestone proper: stage objects load without faulting and the rendered scene contains actual model geometry (not just the clear color / background), stable under a 30 s+ soak. After that, Phase 2 makes it look right (fast3d CC/RM correctness vs gmain.s — GE-specific, no PD analogue) and Phase 3 adds sound + input, largely copy-and-adapt from the PD port (see "PD port as standing reference" above). Commit + push to origin/master at each working checkpoint using the message style PC port: <phase> — <what>.

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