Commit Graph

3 Commits

Author SHA1 Message Date
Sylpheed RE agent
70cff9ca21 re: the 147 ISL built-ins characterised; Stage 02 gates on units, not counts
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.
2026-08-25 12:36:02 +00:00
Sylpheed RE agent
3f13a8ceef re: ISL operand kinds decoded; arguments are staged through local[]
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.
2026-08-25 12:28:04 +00:00
Sylpheed RE agent
7b445916bc re: ISL bytecode encoding decoded; phase-end call sites located in Stage02
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.
2026-08-25 12:21:44 +00:00