D164 docs: root-cause D76 disclaimer screen (linker-adjacency loop bound in front.c, not an image-table bug)

docs/PCPortResearch.md

@@ -845,6 +845,7 @@ covers D24–D69; the log continues in §H (D32 procedure, D70–D121).
 | D153 | **`-level_09` frame ~900–1400 `0xc0000005` = D117/D134 load flakiness, NOT a bug (M-28).** Reproduced 6/6 while the machine was under heavy concurrent build+run load; on a **quiet** machine `-level_09` ran past frame 2400 with 0 heartbeats, no crash. Same false-positive class the docs warn about every session (M-13..M-22, M-25 Silo ~frame 300 freeze). The crash PC was in a system DLL (a `memcpy` off a buffer) and the frame varied run-to-run — both consistent with the port's host-scheduling jitter under load (`osGetCount` is wall-clock, variable-timestep sim), not a deterministic defect. `romdataFixupMusicSeqTable: seqCount 63 exceeds blob capacity 1` is an EXPECTED benign warning on the header-only first `romdataFixupMusicSeqTable` call (music.c:736; the full-size second call at :742 is silent) — not related. **Lesson: don't regression-test while builds/other runs are in flight.** | NOT A BUG — closed. Run anchors on a quiet machine. |
 | D151 | **Watch data all blank — objectives / mission background / M / Q / Moneypenny (M-28, user bug report).** Not a crash (D150 fixed that); every line renders empty. The watch text lives in `propDefs` record types **35** (`WatchMenuObjectiveText`) and **23** (`ObjectiveStart`). In the setup stream each record's 3rd word is a **plain 32-bit language slot id** (see `assets/obseg/setup/Usetup*Z.c` `propDefs[]`: `_mkword(0,_mkshort(0,35)), menu, 11281, 0`). The decomp structs `struct watchMenuObjectiveText` / `struct objective_entry` decode that word as `u16 reserved; u16 text;` and read `text` at offset `0xA` — which only works on the N64 because the id sits in the **low 16 bits of a big-endian word**. On LE, `tools_pc/d88_propdefs.py` `_bswap32`'s the whole word (correct for a 32-bit field), moving the id to the low bytes, so `text` (u16 @0xA) reads `0x0000` → `langGet(0)` → NULL → `get_ptr_text_for_watch_breifing_page` / `get_text_for_objective` return NULL/blank. This is the "briefing/objective text renders blank" side-effect left open under D143 / D150. The per-level lang bank itself IS loaded in-level (`langLoadToAddr(langGetLangBankIndexFromStagenum(stageId))`, `prop.c:1274`). | FIXED (`src/bondtypes.h`, `#ifdef PORT` — `text` is a full `u32` covering the whole word in both structs; N64 `u16 reserved; u16 text;` kept under `#else`). No converter change, no sidecar regen. `nextentry`/`difficulty`/`unkD` unchanged. PORT-LEARNINGS §C. Build compiles clean; interactive re-verify pending (open the watch in any level). |
 | D130 | crash class C2 (Facility `-level_34`, Runway `-level_35`): `import_texture_i8` AV on a wild texture pointer (`0x72181ee8`), baked into the HUD glyph DL by `gDPLoadTextureBlock(gdl, curchar->pixeldata, …)` when the level-title string ("Chemical Warfare Facility #2") renders `#`/`"`. Root cause: `romdataFixupFont` (`port/src/romdata.c`) converts the N64 24B fontchar array to the PC 32B array **in place**, forward-field, backward-glyph. PC−N64 stride = 8, so for glyphs 0/1/2 `d` overlaps `s` by less than the 24B read span and an early field write clobbers a later field's source mid-`for k<5` loop → glyph 1's `width` = `bswap(index)` = `0x01000000`, glyph 2's `pixeldata` = `pcPixOff+(index−pixStart)` ≈ `0x020002e8` → `+= font_base` → wild → fast3d AV. On N64 the array is read-only rodata, never re-laid-out, so no bug there. NOT the model-GDL relocation (`sub_GAME_7F0762E0` / `texLoadFromGdl`) the D124-Facility addendum suspected — `gdl` there is still a segmented `0x05xxxxxx` value so the `& 0x00ffffff` masks are correct, and `texLoadFromGdl` never copies a `G_SETTIMG` for these levels. | resolved — stage all 6 N64 fields in a local `f[6]` before writing any. Facility + Runway now PASS (16→18/21). Probes reverted. |
+| D164 | **Disclaimer / legal screen only draws the first line (D76 root cause, M-31).** `constructor_menu00_legalscreen` (`src/game/front.c:1523`) renders the 12-entry `legalpage_text_array[]` with `legal_text_end = (struct legal_screen_text *)&legalscreen_MRD;` then `do { render; ptr++; } while (ptr < legal_text_end);`. This is a **linker-adjacency assumption**: on N64 `.data` the two file-scope globals are emitted in source order so `&legalscreen_MRD == legalpage_text_array + 12` and the loop count is exactly the array length. mingw/GCC reorders them — in `build-pc/ge007.x86_64.exe` `legalscreen_MRD` links at `0x1401305e0`, **0x60 bytes before** `legalpage_text_array` at `0x140130640` (verified via `nm`). So `legal_text_end < legal_text_ptr` from the start; the `do/while` runs the body **once** (entry 0, "TWYCROSS BOARD OF GAME CLASSIFICATION" — long + CENTER_ALIGN so it wraps to ~2 visual lines = the "classification line + one below" the user saw), then exits. The other 11 legal lines never render. NOT a D68 image-table bug — the legal screen references **zero** `sImageTableEntry`s; it is pure `langGet()` font text via `display_aligned_white_text_to_screen`→`textRender`, plus the 3D `logoinst` model (`subdraw`, absent — D75 family, parked). The D68 fixup and the `GE_IMGT` avenue in the brief are both dead ends here. | **FIX PROPOSED, NOT APPLIED** (`front.c` is owned by another agent this session). One-line `#ifdef PORT` in `constructor_menu00_legalscreen`: `legal_text_end = legalpage_text_array + ARRAY_COUNT(legalpage_text_array);` (N64 `&legalscreen_MRD` cast under `#else`). Same linker-layout class as the D75 loop-bound / D142 enum family. Confidence: **high** — mechanism confirmed by symbol addresses. |
 
 Phase 2 replaced the Phase-1 demo loop with the real `mainproc()` on real OS
 threads, compiled GE's real `src/sched.c`, and brought in PD's fast3d software

docs/PORT-LEARNINGS.md

@@ -367,6 +367,24 @@ a few others use it as their **only** mutual-exclusion primitive. On PC the
   `ALEventQueue` lock) still owed — do it once the steal-log names the
   leaking call site. §F D152.
 
+## D5. Loop bounds that assume linker adjacency of two file-scope globals
+
+N64 decomp sometimes ends an array walk with `end = &nextGlobal;` where
+`nextGlobal` is the *next* file-scope definition in the `.c`. The N64
+toolchain emits `.data`/`.bss` in source order so `&nextGlobal ==
+array + ARRAY_COUNT(array)`; mingw/GCC on the PC target **reorders**
+globals, so `end` can land before the array (loop runs 0–1 times) or far
+past it (walk off the end).
+
+- Instance: **D164** — `constructor_menu00_legalscreen` (`front.c`) bounds
+  the 12-line legal-screen text loop on `&legalscreen_MRD`, which mingw
+  links 0x60 bytes *before* `legalpage_text_array` → only line 1 renders
+  (== the D76 "disclaimer half-drawn" bug; it was never an image-table
+  issue). Fix: `#ifdef PORT` uses `array + ARRAY_COUNT(array)`.
+- Grep for `= &` / `(TYPE *)&` on the RHS of a loop-terminator compare, and
+  any `for`/`while`/`do` whose end pointer is the address of a *different*
+  symbol than the one being iterated.
+
 ## E. Process / method notes
 
 - Investigation loop is: reproduce → env-gated capped probe → root-cause