# Original completion statistics and checkpoints

The native backend now recovers the complete original `08001E48` completion
accumulator and the `08001CF4` / `08001D9C` checkpoint helpers. All three also
compile byte for byte through the requested local decomp.wtf engine, using
ordinary C in `recovered/level_statistics.c`,
`recovered/statistics_checkpoint_capture.c` and
`recovered/statistics_checkpoint_restore.c`. They add 592 exactly matched bytes.

## Completion accumulator

Original completion calls `1231C` before `1E48`. The former captures weapons
and refreshes their statistics rows; the latter performs these writes:

| GAME destination | Source / operation |
| --- | --- |
| +2F0 | Replace with score at +88 |
| +2F4 | Replace with signed body health at local player body+32 |
| +2F8, +2FC | Replace with signed local player protection C6, C4 |
| +300 | Replace with unsigned level byte at +7C |
| +304 | Add elapsed at +0C |
| +308 | Add all 12 spawned counters at +130, stride12 |
| +30C | Add all 12 kill counters at +138, stride12 |
| +310 | Add all 12 player-hit counters at +134, stride12 |
| +314 | Add all 10 weapon **hit** counters at +9C, stride16 |
| +318 | Add accepted pickups at +31C |

The weapon shot counter at +98 is not added. Pickups are accepted items, not
all map objects or secrets: original `1B99C` increments +31C only after an
accepted ordinary contact. Score replaces the saved score; it is not added
again. Arithmetic wraps at 32 bits without saturation. Health and protection
sign-extend from 16 bits. No input counter is cleared by `1E48`. There is no
once-only latch; a second call adds the same counters again.

`ssa_statistics_complete` in `src/statistics.c` implements this with value-only
`SsaLevelStatistics` and `SsaStatisticsTotals` projections. The caller must
commit once per actual completion. Null arguments reject before writes.

## Checkpoint helpers

`1CF4` copies ten complete 16-byte weapon rows from GAME+90 to +1C0 and twelve
12-byte enemy rows from +130 to +260. `1D9C` copies those rows back and clears
only current accepted pickups at +31C. Both preserve elapsed, score, player
vitality, level and campaign totals. The saved rows are not cleared. Native
capture/restore helpers retain these exact boundaries; restoring statistics is
not player respawn, level initialization or a complete continue workflow.

## Native snapshot adapter and limits

`ssa_native_game_statistics` in `src/native_statistics.c` collects the live
native weapon rows, activation counts, combat counters, elapsed time, score,
accepted pickups and player vitality. It uses canonical inventory health and
protection; body health is a native mirror. It copies values only and preserves
the entire game. It rejects unloaded/error/busy games without changing output,
using the same six ownership/query guards as the existing weapon snapshot.

This snapshot observes ongoing counters; it does not run the mutating `1231C`
password-setting counter reset. The new [completion adapter](completion.md)
preserves original capture/accumulate/checkpoint ordering, the setting policy and
bonus-adjusted score. The frontend now commits campaign-session totals and
checkpoint rows after the visible bonus tally, and carries the resulting score
to the next level and its entry snapshot. See [pause/tally integration](completion.md).
High-score/name entry and scores.dat persistence now connect at Quit-run/ending;
see [scores.md](scores.md). Finite-life death/retry/game-over orchestration now
connects too; see [run-exit.md](run-exit.md). Campaign totals currently remain
within the run. An original SRAM/disk format for those totals has not been
established by this recovery, so their persistence should not be assumed from
the older TODO alone. All twelve campaign maps are enabled for manual validation.

## Verification

```powershell
.\decomp.ps1 test-statistics
.\decomp.ps1 test-native-statistics
powershell -NoProfile -ExecutionPolicy Bypass -File scripts/test-statistics.ps1 -SkipBuild
```

`statistics-validation.json` records 8,192 complete original-ROM comparisons per
routine (24,576 total), plus 512 original save/mutate/restore/twice-accumulate
sequences and six null guards under UBSan. No callee is intercepted. Tests
compare whole GAME/player/body blocks, including every untouched byte; they
cover overflow, signed vitality boundaries, distinct shot/hit counters and all
256 level byte values.

`native-statistics-validation.json` and
`windows-native-statistics-validation.json` agree on 27,699 checks, 48 starts,
3,072 actual native gameplay frames, 288 read-only snapshots and 480 rejection
cases across all 16 maps and three difficulties. Jump, H-view and a quick mouse
click are delivered through the actual PC input API. Directed counter fixtures
check every column, high 32-bit values and canonical health separately from
ordinary gameplay. These fixtures are not campaign-completion evidence. GCC
ASan/UBSan/leak detection and MSVC pass.

All 109 portable CMake libraries and 110 Windows libraries build. The complete
portable build exposed an existing Windows-only profile disk test outside a
platform guard; CMake now includes that target only under `WIN32`. Both full
builds pass after that correction. The final audit checks 565 current source
hashes across the four statistics/build reports and confirms the playable
Windows executable remains unchanged.

Live exact matching is now 78/526 functions and 2,816/87,648 catalogued bytes
(3.21%), after 541 compiler attempts. The imported catalogue is incomplete and
does not represent whole-game coverage. The 78-C export and independent rebuild
retain the original ROM SHA-1 `4ff48d8c18b70a5184758f1917343ae85a70858e`.