Chasing where the event code comes from turned up the level above and
corrected my own framing three sections running.
sub_821C6458 has exactly one caller, sub_821C7850, and that caller is
itself a dispatcher -- on a SECOND, outer state field at this+132, five
phases, gated on this+16 == 3. Phase 4 is the title/menu machine I have
been decoding. Phase 0 is sub_821C5690, which the iterate3E notes had
already fingered as the splash mechanics from a completely different
direction. That agreement is the useful check here.
So GamePart_Title has two nested state fields: a phase at this+132
choosing which sub-machine runs, and the state at this+136 inside phase
4. Everything I decoded over the last three iterations -- ten states,
eighteen edges, the event dispatch -- is phase 4 ONLY. Phases 1, 2 and 3
are untouched. I have called that out in REFUTED against my own earlier
wording rather than quietly restating it.
And the event code is forwarded, not created: all five phase handlers are
called with the same (this, r29, r28), where r28 is sub_821C7850's own
third argument passed through untouched. So the event vocabulary is
defined at least one level further up, and finding what 3, 5, 8, 10 and
25 mean means going up again. Not done.
Continuing Q6's last item: the condition on each edge.
sub_821C6458's third argument is an EVENT CODE, and state 4 -- reached
straight after the main menu is installed, so the input-waiting state --
dispatches on it through a second jump table at 0x821c6b7c, 26 cases.
Six are handled and twenty fall through changing nothing:
event 0 -> state 0 (TITLE_SCREEN, back to the title)
events 3, 5, 8, 25 -> state 8 (LOADING)
event 10 -> state 5
So the edges I listed last iteration as "4 -> 0, 5, 8x4" are each now
attributed to a specific event, and the input state's graph is complete.
One thing I deliberately did NOT promote. The main menu has five items, B
returns to the title, and this table has one event to the title, four to
LOADING and one elsewhere. That is a tempting fit -- B plus four items
that load an external archive plus EXTRAS staying inside GP_TITLE -- and
it matches everything measured. It is also a count-match and nothing
more: the events are unnamed, nothing shows event 3 is a particular menu
row, and state 5 installs no named screen so the EXTRAS half has no
support at all. Written down as an observation with that said plainly,
because the same shape of reasoning already cost me DIFFICULTY and
EXTRA_MENU two iterations ago.
Still open: what the event numbers mean, the conditions on edges out of
the other states, and what states 1/3/5/6/7/9 do.
Q6's last open piece was which state leads to which, and it turned out to
be a plain switch.
state = this+136, compared against 9, dispatched through a jump table at
0x821C6498. The ten words at that address disassemble as lwz r16,N(r28)
instructions and are nothing of the kind -- they are the table. That is
the same "self-reference" I flagged two iterations ago as looking like a
jump table; it is one, and the disassembler was decoding its data.
Three states install a named screen: 0 is TITLE_SCREEN, 2 is TITLE_MENU,
8 is LOADING. Eighteen transitions, every one a literal li/stw pair into
the state field, giving the full graph.
It lines up with the behaviour measured weeks of iterations ago without
either side knowing about the other: boot reaches state 0 and A opens
state 2; B at the main menu returns to the title, and 4 -> 0 is the ONLY
edge back to state 0, reached from 2 -> 4; entering a submenu goes
through LOADING and comes back, which is 4 -> 8 at four separate sites
then 8 -> 2. I have marked that as corroboration and said plainly it is
me matching a graph to observations -- the conditions on the edges are
not decoded, so nothing here proves which input picks which branch.
Still open and written down as such: the condition on each edge, what
states 1/3/5/6/7/9 do, and the fact that state 3 is never a destination
in this function, so something outside sets it.
