All re-read twice — the handler, and the thing it calls — because each had
been named from its shape rather than its effect.
* id 11 `yield` -> `end_coroutine`. 0x82272624 is li r11,1 ; li r3,3 ;
stw r11,164(r31), and the dispatcher's r3==3 arm erases the thread from
the active list and returns it to the free list. It destroys the thread.
2945 sites game-wide, 372 in Stage 02 — the most-used built-in there was.
* id 5 `await_label` -> `kill_coroutine(label)`. sub_82273B08 kills the
thread parked at the target pc, or itself if the target is its own pc.
It waits for nothing.
* id 100 `push_trigger` -> `reset_phase_threads`. It clears the trigger
container and then frees every thread whose pc differs from the caller's
— the opposite of pushing a trigger. Corroborated by usage: its 12 Stage
02 sites all sit in the phase terminator, next to timer_stop,
clear_flag(-1) and MARK_LAST_PHASE.
One name recovered from the game's own text: opcode 992 prints
"RequestScriptMessage %s" at 0x820A5700, so id 64 is request_script_message
(2683 sites).
Return codes documented properly: 1 = restart the coroutine from its entry
(previously not recorded at all), 3 = terminate. And the blocking set was
wrong in two places — it is 102, 120, 137, 142, 143. Id 97 does NOT block;
its handler ends `b 0x822724F8`, so it always returns 0.
Unit-operand resolution settled from DATA over all 28 stages rather than by
reading 147 handlers: a slot qualifies only if every value is a valid
symtab-2 index, it takes >=15 distinct values, AND its maximum reaches most
of the table — that last clause is what discriminates, since every small
integer is trivially "in range". 31 built-ins at slot 4, 8 at slot 12, one
at slot 20. It also refutes set_flag's slot 0, whose maximum overruns the
table, and the resolver now declines rather than inventing a name.
New and unexplained: symtab-2 holds two types, 2 and 8, and built-ins 95 and
128 take type 8 at slot 12 in 100% of their sites.
A downstream inference is withdrawn with it: the note reading the live
trigger counter attributed it to "the script arming watches as it goes" via
built-in 100. The measurement stands; the attribution does not.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PMRJjbxLqZtsb5Vb7KunPE
Settled from the disassembly, no run needed. Built-in 69's tail maps the
lifecycle lookup into [phase+164]: handle == 0 takes the early exit at
0x8226AF44 and returns 0, while the destroyed states return 2, 3 or 4 (and two
of those also normalise the record's +16). Those are different values.
So poking rec+4 = 0 made the predicate report ABSENT -- the same answer an
undeployed unit gives -- and never the answer the script branches on. The
condition was polling at 5 Hz throughout and correctly saw 'not here'.
Both null results are now fully explained, and neither was evidence about the
condition: the first poke wrote a field nobody reads, the second wrote the wrong
value into the right field. Simulating a kill needs the handle to stay valid
while the lifecycle lookup returns 3/4/5, i.e. the write belongs in whatever
sub_82301240 reads, not in the script's own record.
Also names built-ins 46/47/48 as squadron_trace / squadron_attack /
squadron_escort in isl.py.
All 28 StageNN.ssb decoded: 2,085,628 bytes, 25,705 call sites, 108 of 147
built-ins used. Verified the survey independently -- 33=0, 34=0, 108 distinct,
hp_pct_test 1955, unit_state 1271, all exact.
global_counter0/1 have ZERO call sites in all 28 stages. The handlers exist and
are wired; no mission calls them. So 'does a wave start after N kills?' is
answered for the whole game, not just Stage 02: no mission counts kills.
Two idioms change how the counts read. hp_pct_test(unit, 0.0) IS a destruction
test -- 1786 of 1955 calls (91%) pass 0.0, and the handler's zero path
additionally requires state == 4 -- so unit_state and hp_pct_test(...,0) are
interchangeable and stages just pick one. And squad_survival_pct is a boolean,
not a percentage: an integer divwu before the x100 means it can only be 0 or
100, and all 29 sites pass a friendly TCAF squadron with threshold 99.9, making
it 'has this escort lost anybody'. The game has no destroy-N%-of-a-squadron
objective.
Outliers: S18-S23 (tutorials) have no flag/trigger machinery at all -- linear
lessons; S16 has no unit predicates, only a descending player-gauge ladder.
Not settled: group_ratio_pct takes two unit indices (blob+4 and blob+12) and its
numerator lookup was not read to the bottom, so it is not being labelled
'percent killed by the player'. isl.py's UNIT_ARG omitted 71/72.
All 25 opcodes now have meanings. Ops 2/4/6/8 are integer compound assignment
(+= -= *= /=) and 3/5/7/9 the float versions; 10 and 11 are integer and float
compare writing three condition bits; 13-18 are je/jne/jl/jle/jg/jge; 21-24 are
push.i/push.f/pop.i/pop.f over deques at phase+44 and phase+64.
The shared-handler question is answered: the dispatcher leaves the opcode in r4
and the shared thunks never overwrite it, so those helpers take an extra opcode
argument and index a secondary table (0x82271448, 0x8227152C).
CORRECTION to my own tool and note: the branch/jump base is [phase+232], which
the phase initialiser sets to 0x24 + the phase's entry from the mission-level
stream -- 0xE4 / 0x14AA8 / 0x24B4C for Stage 02's three phases, not the file's
0x24. Measured on phase 1: base 0xE4 puts 525 of 525 branch targets on an
instruction boundary; base 0x24 manages 188. isl.py had been using 0x24 for
every phase, so its jump targets were wrong throughout. Fixed via
isl.phase_bases().
That also settles two things mission-script-ssb.md left open: offsets ARE
code-base-relative, and 0x1883's operand IS a code pointer -- the earlier worry
that some 'land on IEEE floats' was an artefact of adding the wrong base.
Resolving symbol-table-2 indices turns the bytecode into mission logic. At
0xF524 Stage02.ssb polls unit_state on ADN110, ADN111 and ADN112, updates each
one's objective marker, then latches set_flag(8) -- exactly the
trigger/predicate/set_flag/END_PHASE shape predicted from the disassembly, now
observed in the mission's own code with names the roster tables already gave.
The 12 END_PHASE sites are outro sequences (wait_cmds_drained / fade_sound(3) /
builtin85(3) / wait_s(3) / END_PHASE / yield) -- the terminator, not the
decision.
Fixes a decode bug that hid every argument: the tracker only followed
local[i] = special[0], but the common form is an immediate written straight into
local[i] (k=01,03), so every unit predicate printed with NO arguments. The
disassembly looked complete while being empty exactly where it mattered.
Also records the live probe result: the phase mirror at [*(0x828F35F8)+236]
stayed 0 for ~530s of actively-hunting flight, no advance observed -- which is
what the static analysis predicts for phase 1, since ChangePhase only posts once
the ordinal exceeds 1.
Table at 0x8227226C is 147 big-endian absolute VAs (verified structurally: it
ends exactly where the first handler begins, all targets inside sub_82272220).
Arguments are not in the instruction -- every handler does c_str() on
[phase+20], a packed blob, which is what the local[] staging fills. Return 2 =
yield; five built-ins block by skipping the pc advance.
Recovered the ScriptPhase state layout: 32-entry float and flag register files,
int/double result registers, the timer block, and the runtime unit array at
+324 indexed by symbol-table-2 index -- a direct hook from bytecode call sites
to the two .ssb symbol tables.
Spot-checked two claims against the disassembly rather than trusting them: id 4
loads a DOUBLE into the thread countdown and returns 2 (wait_s), and id 24 reads
current/initial squadron member counts (squad_survival_pct). Both exact.
Counting Stage02.ssb: unit_state 255, hp_pct_test 167, dist_lt 92, unit_alive
71, unit_relation 52 -- and squad_survival_pct, group_ratio_pct and the two
global counters are NOT called at all. So Stage 02's phases are gated on named
units (destroyed / HP / proximity), never on an aggregate count, even though the
kill-counter primitives exist in the VM. That answers the standing 'next wave
after N kills or after an event?' question for this stage: specific units, not a
number.
isl.py now names the built-ins, so the run-up to the first END_PHASE reads
wait_cmds_drained / fade_sound(3) / builtin85(3) / wait_s(3) / END_PHASE.
Not settled: 3 handlers unresolved (55, 75, 105); the 1024-slot interpreter
command table is only partly recovered.
Resolver table 0x82271D74 gives four kinds: 0 global[i], 1 immediate,
2 special[i] ([phase+164]/[phase+168]), 3 local[i] ([phase+20+i]). Byte[0] is
the rvalue kind, byte[1] the lvalue kind, so the recurring instruction pair is
argument staging -- values land in local[] at offsets 0,4,8,0xC and the next
call consumes them. A built-in's arguments are not in its own instruction.
Fixed a decode that would have been believed: immediates in set.f are DOUBLES
carried as two words (op 1 stores with stfd). Reading the high word as a float
gives 2.125 where the script means 3.0.
isl.py now tracks staging and prints call arguments, so the run-up to the first
END PHASE in Stage02 reads as builtin=64(0x42,2,1,9,1,-1) / 120 / 59(3) / 85(3)
/ 4(3) / 6. Three built-ins taking 3 just before the phase ends look like a
wait-seconds family -- flagged as unconfirmed until the built-in table is read.
Read the encoding off the interpreter rather than guessing: instruction is a
big-endian u32 whose LOW byte is the opcode (25 of them, table 0x822635FC),
byte[2] is the instruction length -- every handler advances the pc by it -- and
bytes[0..1] are operand kinds. Op 12 is a jump whose operand is relative to the
code base [phase+232], which settles that offsets are code-base-relative for
this opcode. Op 19 is the built-in call: id in word@+4, and word@+8 is a
monotonically increasing STATEMENT id (0x245, 0x248, 0x24A, ...).
Confirmed by disassembling Stage02.ssb: the stream decodes cleanly from the code
base and routines terminate on ret exactly where expected.
Scanning the code region on the call encoding: 2846 call sites, 73 of the 147
built-ins used. The phase-control ones are located -- built-in 6 (end phase) at
12 sites, 62 at 3, 39 (mark last phase) at 8 -- so a phase has several exit
paths, as a mission with win and lose branches should.
New tool tools/re-capture/isl.py with --calls and --to (resync-into-target,
needed because instructions are variable-length so you cannot walk backwards).
Not settled: the 147 built-ins are uncharacterised, so this is structure without
meaning -- we can see THAT a phase ends, not WHAT was tested.
