# ✅ `sub_822737C8` is the coroutine spawner — and its seven callers name the whole start-up path

Asking *who calls the thing the timeline calls* turns out to enumerate every way
an ISL routine can begin.

`sub_822737C8(phase, base, offset)` — `add r9, r4, r28` computes `base + offset`
early on, so the third argument is a phase-relative code offset.

## The seven call sites

| site | in | what it starts |
|---|---|---|
| `0x82271030` | **`sub_82270DF8`** — the phase initialiser | the phase's **main entry** (the `0x1883` record's third word) |
| `0x822724D0` | the built-in stub region | `start_coroutine`'s target |
| `0x82274934` | **`sub_822748D0`** — the timeline walker | a scheduled routine |
| **`0x8226D8D0`** | **`sub_8226D740`** — the per-frame engine→script drain | an offset from **`[node+112]`** |
| **`0x8226DA10`** | the same drain, second path | the same `[node+112]` |
| `0x82273938` | `sub_82273910` | not read |
| `0x82264080` | `sub_82264058` | not read |

## ✅ The phase's main entry — a correction

`isl-stream-entry-points.md` called the record's third word a **size**. It is
not: the initialiser hands it to the spawner as an offset.

* **44 of 44 records land on the instruction stream — 100 %, against a 25.0 %
  control.**
* All three of Stage 02's targets begin with the same prologue,
  `special[0] = 0 ; local[0] = 0 ; call builtin116(0)`, which is a routine entry
  and not a length.

So the record reads `0x1883, base, MAIN_ENTRY, 0, code_end, force_end_handler`.

🟡 Seeding it changes nothing measurable — every main entry was **already**
among the CFG's entry points by another route — so this corrects the *meaning*
of a field without moving any coverage number.

## 🔴 WITHDRAWN: "the drain spawns from `[node+112]`"

The two calls inside `sub_8226D740` both do

```
lwz  r5, 112(r31)      ; the routine offset, out of the node
lwz  r4, 232(r29)      ; the phase's code base
bl   0x822737C8
```

**`r31 = r1 - 256`** — it is the **stack frame**, so `+112` is an output slot,
not a node field. See [structures/isl-trigger-node](structures/isl-trigger-node.md),
which reads the node properly and also refutes the follow-up hypothesis that the
trigger carries a routine offset.

## 🟡 Not settled

* **`+112` is a field of *some* node** — this does not show the node comes from
  the trigger queue at `phase+272`. That link is exactly the over-reach
  `isl-builtins.md` already recorded and withdrew once; it is not asserted here.
* **Two callers unread**: `sub_82273910` and `sub_82264058`.
* **Whether the drain's nodes explain the unreached routines** is untested. It
  is a lead, not a result.