The serializer recovery reaches this repo as a generated wire schema
(include/generated/sots_stream_schema.h, 386 classes / 2042 items): for each
class, the ordered sequence of items its Write puts on the stream. Facts only —
no field offsets, no sizeof, no strides. This engine reads and writes the on-disk
format; it does not inherit the original's memory layout.
The table is a specification, not a program: the recovery is a linear pass over
Write, so it cannot see Write's branches (StarShip's BQ2 is gated on hbq but
listed unconditionally) and it flattens container loops. A codec driven off it
would desynchronise. The hand-written io() shapes stay the codec; SchemaProbe
(probe.h) walks them with every branch taken and test_wire_schema LCS-aligns
that against the table — 56 shapes bound, 657 items matched, 0 mismatches.
Four defects the check found, all invisible to a round-trip test:
- SystemParams field 1 is a string, not an int. It is the empty string in
every save, and an empty string is four zero bytes — byte-identical to the
int 0, so it round-tripped by luck. A named planet would have desynced.
- ObservedTech/ObservedWeapon odet is a bool, not an int. Byte-safe only
because a 4-char tag makes a bool item and an int item both 12 bytes.
- SpeciesRatios nv and ShipRecords srbd are counts, not fields.
CoverageArchive separates items a field names from items a Node merely carries,
because a byte-identical round trip is not a coverage claim. Typed coverage of a
real save goes 37.9% -> 97.1% (97.2/97.2/97.6 on the others) with the round trip
still byte-identical, by typing TechTree (both NumTechs sections), Events,
ShipRecs, sprjs, civr, comms, spy2, spymgr, aid, Ojvs, AIEnf, FNG, trdmgr and
the Des section/gun-bank tree. Ratchet at 95%.
trdmgr resolves a recorded trap: ServerTradeManager's Read/Write really are the
inherited no-op, but the call is virtual and ServerTradeManagerImpl has the real
serializer. Same shape resolves IServerSpyManager -> ServerSpyManager.
ctest 34/34, clean_room_check OK, test_save skips cleanly with SOTS_SAVES_DIR unset.
Ran the queued VM140 verification of docs/P-events-wiring.md §4 with main dd38117
unchanged, cross-built on CT111 as eventlive-dd38117-20260908T0916Z and staged to
C:\SOTS\shimdist-v.
First End Turn on shim.cfg.recapb3 unchanged: 3 calls, 3 compared, 0 divergent,
tracecmp exit 0. Every field lane P forecast for call 0 read as predicted, including
turn=3, events_turn_bucket_exists=true, events_dedup_risk=0, next_id 3->4 on both
sides and observed_techs.bytes unchanged on all three calls.
Five End Turns: exit 1 with two divergent calls instead of three, both short by
exactly one id (7/6 and 12/11) — the unmodelled EVENT_TECHS_UNLOCKED, at the size
lane P said it would be.
sizeof(Game::ObservedTech) measured live at 44 on both completion calls
(observed_techs.bytes 440->484 and 484->528), confirming a static pin behaviourally.
That confirmation was written into the RE repo's addresses.json and has already
reached the generated header on main, so this branch carries docs only.
One deviation from lane R: rng diverged on call 9 because the completed tech had
research_roll_pending set, so the OnTechResearched callback drew one word ours does
not. That is a declared out-of-scope boundary, and it means lane R's "RNG 15/15" was
workload luck rather than a property of the hook.
Also closed the Zuul double roll behaviourally on a species-5 save made for the
purpose: 8 calls, 0 divergent, and all four species-5 researching calls advance the
generator by two with ours matching bit-for-bit.
clean_room_check.sh OK; host ctest 33/33. Run as separate commands.
New fpu_force module (4 register-transparent asm stubs, same pattern as the M0
Initialize hook, so the [unverified] prototypes of the turn-gate functions are
never relied on) plus two shim.cfg keys:
fpu.force=<cw>|off fldcw at StrategyClient::EndTurn and
StrategyServer::BeginProcessTurn, and nowhere else
fpu.sample_ticks=on|off per-frame sampler, logs only when the word CHANGES
Forcing is deliberately one write per turn: re-forcing inside the pipeline would
guarantee the value is present without proving it ever held, which is the exact
false negative this experiment has to avoid. Verification is kept separate --
StrategyServer::ProcessTurn is hooked sample-only, and its reading plus the
existing per-hook fpu_cw fields (38 samples per turn across phases 4, 6 and 8)
are what establish that the setting lasted the whole turn.
Six shim.cfg variants, identical apart from the fpu.force line, and docs.
Used to settle STATE_CHECKSUM.md 3.5: 53-bit and 64-bit x87 produce byte-
identical turn results, so an x64/SSE port has no double-rounding budget to
preserve; 24-bit and round-up each move exactly one thing. Findings and evidence
live in the notes repo (findings/subsystems/fpu-precision-sensitivity.md).
clean_room_check.sh OK; host ctest 32/32.
The header's ObservedTech notes carried a std::string size of 0x18. That was a
mis-attribution: the element's +0x24 word is the name string's trailing (empty)
allocator, not a data field. sizeof(std::string) is 0x1c binary-wide, confirmed
against every serializer in the original.
ObservedTech is now fully mapped, so the two research-hook comments that said
sizeof and the append site were unpinned are corrected. The region stays
declared-not-modelled -- appending is a behavioural change this hook does not
make -- but its byte delta now has an exact expected value (44 per completion),
and the note records that the original's append de-duplicates by tech name, so a
naive push_back would diverge on re-observation.
clean_room_check: OK. host ctest: 33/33.
TechTree::ProcessResearch's events region now compares a modelled value instead of
reporting a known defect. ours posts the pass's events into its own
sots::events::EventStorage, seeded from a scan of the owner's list taken BEFORE the
original runs, and writes only the counts into the region's scratch copy. The game's
PostEvent is never called and no live byte moves; replace mode still posts nothing,
because a bumped EvNxID with no record behind it would corrupt the oracle's save.
- game/events: PostResearchPassEvents (the decision half, pure) + KeylessEventText
- shim/hooks/event_inputs (new lib shim_events, host-tested): the live<->model adapter,
carrying game pointers as explicit uint32 so a 64-bit host build cannot alias them
- research hook: the wiring, a new observed_techs region for ServerPlayer+0x274, and
turn / events_next_id_in / events_dedup_risk in the args so the count model's own
assumption is measured rather than assumed
- EVENT_TECHS_UNLOCKED is NOT posted: its trigger is pinned but needs SetResearched's
unlock cascade, which ours does not run. The driver takes the unlock list as an input
and is handed 'no list', so a missing input cannot look like a modelled negative.
Predicted residual: next_id short by exactly 1 on a completion call.
ctest 33/33 (shim_events_unit is new), clean_room_check OK. The shim TU is
syntax-checked only: no MinGW cross toolchain on this box.
See docs/P-events-wiring.md for the exact prediction for the next VM run.
The behavioural compare found 8 of 45 StrategyServer::MoveFleet calls diverging by
one ULP on a position component. Read off the instruction stream, the cause is that
the engine's vector normalise narrows to float32 four separate times and we kept
everything in double:
delta.c = f32(dest.c - pos.c) stored back to a float32 slot before normalising
sumsq = f32(x*x + y*y + z*z) products/adds in 53-bit regs, only the SUM stored
len = f32(sqrt(sumsq))
inv = f32(1.0 / len) a reciprocal, MULTIPLIED through, not three divides
dir.c = f32(delta.c * inv)
and the same call returns the leg distance, so it is never recomputed in a wider
precision either. The position tail was already right, which is why the error was a
constant absolute ~1.2e-7 (half an ULP of the inputs) rather than a formula error.
Adds NormalizeVec3 / StraightLeg / StraightLegDistance / AdvanceAlongUnitDirection
and rebuilds AdvanceAlongDirection on them; the movement hook now takes both the
direction and the distance from one StraightLeg call, as the original does. The
arrival test is an exact float compare, so the distance has to be that same float32.
Tests pin float32 BIT PATTERNS, not tolerances: one case per narrowing plus four
independent legs component by component. A CHECK_NEAR would pass against the old
arithmetic.
sim::Distance is left in double on purpose and flagged at its declaration: it now
serves only the node-line/stutter geometry, which very likely needs the same
treatment but has zero behavioural coverage to correct it against.
Live, same VM/save/workload, run twice by this lane:
control recap-7584bad-20260908T0615Z 45 calls, 45 compared, 8 diverged, exit 1
fixed mf-45bdf7d-dirty-20260908T0721Z 45 calls, 45 compared, 0 diverged, exit 0
with identical arguments, identical pos.before and identical ORIGINAL pos.after on
all 45 calls. The control reproduced the eight divergent call_ids exactly.
Coverage unchanged and still thin: all 15 moving calls are the same straight-run
waypoint type; types 2-5 were attempted and could not be reached (the only player
that would travel a node line has no ships on this save). See docs/M-movefleet.md.
ctest 32/32; tools/clean_room_check.sh OK.
Five hooks recaptured; no source change needed. ProcessResearch's over-budget
event now diverges as one line instead of a 609 KB save diff (15 calls, 3
diverged, RNG 15/15). ComputeBudget holds at 0 over 4284 compares but only 20
distinct states and 13 always-zero slots. MoveFleet diverges on 8 of 45 calls by
1 ULP of position - B4's clean verdict was a one-sample verdict. First guarded
captures for OnTechResearched (RollResearchEvent draw finally fired and matched),
the colony turn and MoveFleet. Guards mapped SetResearched live and found an
undeclared observed-tech vector append.
Recovers the game's event-posting API so the engine can post events and the
compare harness can see them. Until now the owner's event list was invisible to
every layer: B3's replace-mode oracle failed by exactly one item across 40,300
(an unposted EVENT_RESEARCH_OVERBUDGET) while its compare read clean, and B2's
clean compare bounds the economy fields only.
New pure module src/game/events:
* EventStorage / TurnEvents / PlayerEvent -- the list is bucketed by TURN, not
flat, which the save-editor struct notes had wrong.
* EventStorage::Post reproducing the original's rules, including the four that
change save bytes: the FLT_MAX (not infinity) default position; action 0 with
no subject and no position storing as 2; per-bucket dedup that compares
message/image/location/position/action but NOT summary; and EvNxID starting
at 0 and being promoted to 1 on the first post.
* PruneOldTurns reproduced with its off-by-one: of a leading run of buckets
older than turn-50 it erases n-1, so one stale bucket always survives. The
survivor is serialized, so correcting it would diverge.
* research_events: the five events the research path raises, their EvImg
identifiers and string-table keys, and the 0.8 completion split evaluated
against (double)0.8f rather than the decimal 0.8.
Localized text is deliberately absent: only the EVENTSUM_/EVENTMSG_ keys are
here and the text resolves through a caller-supplied lookup, as the game does.
The four event offsets the B3 hook carried as local literals now come from the
generated header; they are read off instructions rather than inferred from the
save schema.
tests/game_events: 112 checks including a replay of the event list
turn3-state.sav actually holds. ctest 31/31 -> 32/32.
docs/E-events.md carries the proposed region and Coverage wording for the next
B3 recapture.
