isl-builtins.md carried the trigger queue at phase+272 a long way -- layout, live
count at +272+20, the generic appender sub_8226EAB8 -- and stopped at "what actually
appends a node is still unidentified", proposing a gdb watchpoint on a running
emulator. It is a static question after all.
sub_8226EAB8 is a shared helper with 16 callers, so it cannot be identified by name.
But the corpus records that the trigger container EMBEDS its inner list at +12, so the
appender must hand it container+12. Only two of the sixteen callers do, and one sets
its base 34 instructions earlier:
8226A22C addi r29, r24, 272 ; r24 = the ScriptPhase
8226A2B4 addi r3, r29, 12 ; -> phase + 272 + 12
bl 0x8226EAB8
phase+272+12 is exactly the inner list whose count the corpus watched at +272+20.
sub_8226A0D8 is ScriptPhase vtable SLOT 28, which is what BUILT-IN 25's stub
tail-calls, and there are ZERO real `bl 0x8226A0D8` instructions in the image -- it is
reached only through the vtable. So the queue is populated by the SCRIPT, retiring
the residual "the engine moves records into the phase's queue each frame" reading that
isl-builtins.md had already flagged as unsupported by its own call site. Built-in 25's
arguments agree with two independently measured tables: UNIT_ARG (a unit at local[4])
and SYM1_SLOTS[12] (a symtab-1 name at local[12]).
REFUTED in the same pass, with a control: built-in 25 does NOT carry the coroutine
entry that a trigger fires, which would have seeded the 389 routines reachable from no
static entry. Taking each staged operand as a code offset from the phase base, 0 of 8
land on an instruction boundary, against 38.7% for an arbitrary 4-aligned offset --
below chance, not above it. And the scale is wrong regardless: built-in 25 has only
2 call sites in Stage 02.
So what starts the unreachable routines is still open, and it is not this. A trigger
node's own layout and its consumer are unread, and built-in 25 stays unnamed.
