PC port: Phase 1.5 — root-cause D32 Part B (D33): ROM big-endian

structured fields + x86-64 loop-stride bug; fix designed, handoff updated

- Finding D33 in docs/PCPortResearch.md: the .z64 stores multi-byte
  structured fields in big-endian byte order (bit-packed streams raw);
  per-field load-time transform rule (u32 bswap32 / u16 bswap16 / u8
  identity) validated over all 173 animation entries; full blob layout
  mapped; exact reproduction of the gdb-observed garbage values.
- Second root cause: expand_ani_table_entries iterates s32** (+8 bytes/iter
  on x86-64 vs +4 on N64), rebasing only even-indexed entries (verified in
  compiled binary). Fix design: romdataFixupAnimationData() in port/, one
  call between romCopy and expand, s32* loop stride fix.
- docs/HANDOFF.md rewritten with the implementation task; AGENTS.md phase
  status updated. tools_pc/disasm.py (BE ROM research tool) added.

AGENTS.md

@@ -4,7 +4,7 @@
 
 - `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–D32 in §11; current handoff + plan in §H).
+- **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
@@ -47,7 +47,7 @@ Run `/linkcheck` for this sweep. Record new findings in `docs/PCPortResearch.md`
 - **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 (load-time rebase in `expand_ani_table_entries`) open. Recurring sub-task: ABI/layout fixes per the D32 procedure (§H) as more asset loading is reached.
+- **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. 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.