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Map sorting and usecode

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MaddoScientisto 2026-03-26 23:12:38 +01:00
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docs/usecode-roundtrip-ir.md
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@ -790,4 +790,19 @@ The strongest present path to a usable compiler/decompiler is:
5. Attach ScummVM event and intrinsic names as hints, not as truth.
6. Recompile by rebuilding the original class header and event table layout first, then re-emitting decoded and opaque ops together.
That gets to a reversible editor sooner than waiting for a full semantic VM recovery.
That gets to a reversible editor sooner than waiting for a full semantic VM recovery.
## **Recent Research (2026-03-26)**
- **Root Cause:**: The structuring pass left forward/back-edge loops and counted-loop headers detached in fallback output, which produced unstructured pseudocode for some bodies (notably BART slot 0x0F).
- **Renderer Fixes:**: Added a conservative loop-lifting helper and a restricted infinite-loop lift in the partial fallback renderer to fold loops into structured blocks where safe. See the modified renderer at [tools/poc_crusader_usecode_parser.py](tools/poc_crusader_usecode_parser.py).
- **Validator Added:**: A lightweight pseudocode syntax/label validator was added to detect brace mismatches and missing goto/label targets before exporting pseudocode.
- **Tests:**: Added and adjusted unit tests in [tools/tests/test_usecode_structuring.py](tools/tests/test_usecode_structuring.py) to guard loop-lifting behavior and fallback conservatism.
- **Corpus Validation:**: Ran a corpus-wide render+validator pass over 977 decoded bodies; result: `TOTAL_BODIES=977, FAILURES=0` (no syntax/label failures).
- **Real-World Output:**: Regenerated the BART pseudocode file — [USECODE/EUSECODE_extracted/pseudocode/BART/slot_0F_enterFastArea.txt](USECODE/EUSECODE_extracted/pseudocode/BART/slot_0F_enterFastArea.txt) now shows an outer `while(true)` with nested structured branches and counted loops instead of detached labels.
- **Scope & Safety:**: Fully-structured renderer remains conservative; the loop-lifting helper is reused where safe. The outer infinite-loop lift was narrowed to partial fallback after tests revealed regressions when it was too broad.
- **Remaining Semantic Gap:**: Expression/comparison operand polarity still needs correction (some counted-loop conditions show inverted comparisons). Next work: fix operand ordering in the expression builder so loop headers reflect correct comparison direction.
- **Next Steps:**: (1) Implement compare-direction fix in the expression builder and add small semantic regression tests, (2) re-run unit tests and a corpus-wide render+validate sweep, (3) regenerate affected pseudocode files for inspection.
- **Files of Interest:**: [tools/poc_crusader_usecode_parser.py](tools/poc_crusader_usecode_parser.py), [tools/tests/test_usecode_structuring.py](tools/tests/test_usecode_structuring.py), [USECODE/EUSECODE_extracted/pseudocode/BART/slot_0F_enterFastArea.txt](USECODE/EUSECODE_extracted/pseudocode/BART/slot_0F_enterFastArea.txt).
If you want, I can (a) implement the comparison/operand polarity fix next, (b) run the unit tests and a fresh corpus sweep, and (c) open a PR-ready commit with these doc and code updates.