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re: find the menu screen id and cursor in guest memory

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Menu navigation here has always been screenshot-driven, which is unusable under
--gpu=null -- the only configuration where the game does not hit the
software-rasterizer freeze.  Without a memory signal, the one backend that runs
is the one that cannot be steered.

Snapshotting 0x82800000+3 MB at each menu of a rendered run and keeping the
4-byte words that differ between screens and hold small integers leaves exactly
four of 786 432.  One has the property that matters -- it changes on a screen
transition and holds steady when only the highlight moves:

    0x828A690C  screen id     1 title, 3 main menu, 4 extras
    0x828F38AC  menu cursor   (second copy at 0x828F38BC)
    0x828F37B4  per-menu value

Verified on a fresh --gpu=null run with no display at all, driving the same keys
blind: title 1/2/12, main menu 3/4/45, after 4x down 3/12/45, extras 4/14/49 --
4/4 exact against the rendered run, across two runs and two GPU backends.  That
is the check that matters, since this corpus has already had to mark one runtime
address run-dependent.

tools/re-capture/menu_state.py reads them; `menu_state.py watch` prints on
change.

Open: the rest of the sequence into a mission.  Blind driving reached extras
(screen 4) and a further A did not move it, so MISSION SELECT needs a cursor
move first.  Screen ids beyond 4 are unmapped, and the rendered run freezes on
entering that screen -- so map ids up to the freeze, then step blind past it.
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Sylpheed RE agent
2026-08-26 18:21:04 +00:00
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# The menu's screen id and cursor, in guest memory
**✅ Found and verified 2026-08-26.** Menu navigation in this corpus has always
been driven by screenshots. That is unusable under `--gpu=null`, which is the
only configuration where the game does not hit the software-rasterizer freeze
([`mission-freeze-heap-exhaustion.md`](mission-freeze-heap-exhaustion.md)) — so
without a memory signal, the one backend that runs is the one that cannot be
steered.
## The words
| address | meaning |
|---|---|
| **`0x828A690C`** | **screen id** — `1` title, `3` main menu, `4` extras |
| **`0x828F38AC`** | **menu cursor** (a second copy at `0x828F38BC`) |
| `0x828F37B4` | tracks the screen, distinct value per menu |
## How they were found
Snapshot `0x82800000` + 3 MB at each menu of a **rendered** run, then keep the
4-byte words that (a) differ between screens and (b) hold small integer values.
Of 786 432 words, exactly **four** qualified — and one of them,
`0x828A690C`, has the property that matters: it changes on a screen *transition*
and stays put when only the highlight moves.
screen: title -> main menu -> (4x down) -> extras
828a690c: 1 -> 3 -> 3 -> 4 <- screen id
828f38ac: 2 -> 4 -> 12 -> 14 <- cursor moves with the highlight
828f37b4: 12 -> 45 -> 45 -> 49
## ✅ Verified against a second run on a different GPU backend
The values were then read on a fresh `--gpu=null` run — **no display at all** —
while driving the same key sequence blind:
| step | rendered (lavapipe) | blind (`--gpu=null`) |
|---|---|---|
| title | 1 / 2 / 12 | **1 / 2 / 12** |
| main menu | 3 / 4 / 45 | **3 / 4 / 45** |
| after 4× down | 3 / 12 / 45 | **3 / 12 / 45** |
| extras | 4 / 14 / 49 | **4 / 14 / 49** |
**4 / 4 exact**, across two runs and two backends. That is the check that matters:
the words are not run-dependent, unlike the OB counter address this corpus had to
mark run-dependent earlier.
`tools/re-capture/menu_state.py` reads them (`menu_state.py watch` polls and
prints on change).
❔ Still open: the rest of the sequence into a **mission**. Blind driving reached
`extras` (screen 4) and a further Ⓐ did not move it — `4 / 14 / 49` twice — so
MISSION SELECT needs a cursor move first. The screen ids beyond 4 are unmapped;
the same snapshot-and-diff method extends to them, but it must be done on a
rendered run, and the rendered run **freezes on entering that screen**. The way
through is to map the ids up to the freeze and step blind past it.