goldeneye-pc-port/AGENTS.md

AGENTS.md — GoldenEye 007 PC Port

What this is

• n64decomp/007: WIP decompilation of GoldenEye 007 (N64), byte-matches US/EU/JP ROMs.
• Active work: PC port modelled on the Perfect Dark PC port (same Rare "Indy" engine family).
• Read docs/PCPortResearch.md first — architecture, GE-specific RSP deltas, phased plan, and review findings (A1–D33 in §11; current handoff + plan in §H).
• Starting a fresh session? Read docs/HANDOFF.md — the paste-ready brief with the immediate task, standing procedure, and environment gotchas.

Non-negotiables

1. N64 build untouched. Makefile, tools/, rsp/, ld/ belong to the N64 build. Never modify them for the PC port.
2. Game logic is unmodified. The decomp's control flow and behavior are ground truth for 1:1 fidelity — never change them. All N64 hardware dependencies are satisfied by the port/ layer; if a game file seems to need a behavioral change, stop — the fix belongs in port/. Narrow exception (ABI/layout only): the 32→64-bit transition forces a small class of mechanical, semantics-preserving edits that cannot be isolated in port/ — chiefly pointer-width reconciliation in ROM-serialized structs (a struct with a 32-bit-pointer field misaligns when read as 64-bit). These follow the PD ground-truth pattern (store the embedded address as u32, cast to a real pointer at the use site), change no logic or behavior, and are each documented in docs/PCPortResearch.md §F/D3x. No other game-code edits are permitted.
3. Region macros mirror the Makefile. CMakeLists.txt REGION_DEFS must match the N64 Makefile's per-region macro set exactly (finding A1). Divergence = silent branch divergence + link failures.
4. src/libultrare/Makefile.libultrare is ground truth for original-vs-Rare libultra files (finding B3). The PC build compiles: libultra/audio, libultrare/audio (drvrNew/env/reverb), libultra/gu, and libultrare/io/vitbl.c only. All other io/ + os/ files are excluded and shimmed in port/src/libultra.c.
5. rsp/graphics/gmain.s is the RSP ground truth — the authoritative reference for which GBI commands GE emits (modified fast3d, 1545 lines). We do not run it on PC; port/fast3d/ replaces it. Use it to validate the software RSP's command decoding and the custom CC/RM modes.

Critical files

File	Role
docs/PCPortResearch.md	Research + plan + findings (A1–C2). Read first.
CMakeLists.txt	PC build (parallel to the N64 Makefile). Source list + REGION_DEFS live here.
port/src/	Shims: libultra.c (OS API), gesched.c (scheduler), n64stubs.c (boot/TLB/FPU/rmon), random.c (PRNG ported verbatim from random.s), ucode.c (microcode segment markers), main.c, video.c, …
port/fast3d/	Software RSP (adapted from the PD port). The main Phase 2 work.
rsp/graphics/gmain.s	GE's RSP ucode — ground truth for GBI/CC/RM.
PD_PORT_CHECKOUT	Perfect Dark PC port checkout — ground truth for the port layer. Its port/fast3d/ is the starting point for ours.

Build

./build-pc.sh ntsc-final   # or pal-final / jpn-final

Needs CMake + SDL2 + zlib + OpenGL (MSYS2 packages: see build-pc.sh header). ROM goes in ./data/ (not distributed).

Verification ritual (after any build-affecting change)

1. Undefined symbols. Every symbol referenced by the compiled set (see CMakeLists.txt: SRC_GAME, SRC_ENGINE, SRC_LIBAUDIO, SRC_LIBULTRARE_AUDIO, SRC_LIBULTRARE_DATA, SRC_GU, SRC_PORT*) must be defined exactly once in the compiled set or in port/. Symbols that live in EXCLUDED files (libultra/io/*, libultrare/io/* except vitbl.c, libultra/os/*, libultrare/os/*, sched.c, rmon.c, vi.c, src/*.s) must be provided by port/src/libultra.c, gesched.c, n64stubs.c, random.c, or ucode.c.
2. Duplicates. No symbol defined twice across the compiled set (watch sp_* stacks, rmon*, os* shims, segment markers).
3. Syntax. Every touched file must parse; once the toolchain is installed, ./build-pc.sh is the final word.

Run /linkcheck for this sweep. Record new findings in docs/PCPortResearch.md §11 style (next label after the last used).

Phase status

• Phase 0 (scaffolding): done, committed.
• Compile+link milestone: all ~235 TUs compile and ge007.x86_64.exe links clean (ninja ge007 -k 0, 236/236). Findings D7–D17 in docs/PCPortResearch.md §11; asset stubs in port/src/assetstubs.c, fast3d no-ops in port/src/gfxstub.c (delete when real fast3d lands).
• Phase 1 (boot to window): done — ROM loads/validates/maps at cart base 0x10000000 (romdata.c), SDL2 window + GL clear loop (video.c), absolute asset symbols from scripts/gen_romassets.py → port/src/romassets_<r>.s (findings D18–D23).
• Phase 1.5 (boot to first frame): IN PROGRESS — mainThread runs through bossInitMainthreadData(); D31 (langInit file-load SIGSEGV) fixed via real-zlib decompression (port/src/rzdecomp.c, replaces the excluded src/game/decompress.c+zlib.c). Current blocker is D32 (ROM-struct pointer-width): Part A (u32 layout in ModelAnimation) done; Part B root-caused (D33) — the ROM stores structured fields big-endian (per-field load-time fixup needed) + an x86-64 loop-stride bug in expand_ani_table_entries; fix designed, implementation next. ROM dump verified against the No-Intro good dump (byte-identical, header CRCs re-checked — tools_pc/romverify.c). Recurring sub-task: ABI/layout fixes per the D32 procedure (§H) as more asset loading is reached.
• Phase 2 (rendering): bring in PD fast3d (replaces port/src/gfxstub.c), verify custom CC/RM modes against gmain.s, port the scheduler; replace asset stubs with ROM-backed data (D16). Assumes ABI-clean data loading from Phase 1.5.
• Phase 3 (audio + input): libaudio → SDL; decide the ASP strategy (C2: aspMain* dummies in ucode.c).
• Phase 4 (saves + polish): file-backed EEPROM; PFS/motor already no-op stubs.