# Session save — to be continued

Date: 2026-10-02. HEAD: `7dbd516` (`express-draft-v1`). Tree clean.

## Where we are

`src/compiler/` holds the re-read compiler: `COMPILER/SCANNER/ERRORS/CODEGEN`
fully renamed + verified clean of numbered identifiers; `SYMTAB.MOD` draft v1
(988 lines, 27 FIXMEs); `EXPRESS.MOD` draft v1 (1489 lines, 137 FIXMEs, 20
FORWARD work-list helpers); `SYMTAB.DEF` expanded (words 10–27); `FRONTEND.md`
export map incl. newly found EXPRESS internals; `docs/compiler/` analysis.

## How we work

* Upstream dirs git-ignored; only `docs/`, `src/`, `SUMMARY.md`, `SESSION.md` versioned.
* Decompile in parallel background workers (3–4 groups per module), each returns
  Modula-2 with `{/* offset */}` comments; assemble + normalize via script
  (`Compiler.word6–26`, `Scanner.word2–12`, `Doubles.proc5–11` mappings);
  verify with `grep -nE '\b(param|local|global|proc|PROC)[0-9]+\b'`.
* Drafts are unverified by design: MCD `unassemble.c` diff still pending for all.
* Commit per step, tag per milestone (`*-v1`).

## 2026-10-03: audit + proc32 applied (`audit-01`)
proc32 WriteOutputFiles added; 8 SYMTAB + 9 EXPRESS signature swaps applied
(def headers; bodies/calls positional-consistent by construction); STMT+PASS1
all KEEP; D1/D2 resolved (map stands); CappedStrLen=StrLen alias noted.
Next: GENZ80 recon + MCD-diff verification harness.

## 2026-10-03: GENZ80 recon + MCD-diff harness (`genz80-harness-01`)
GENZ80: no binary/disassembly anywhere (only call site + overlay-table
strings); trigger chain partly open (no setter of nativeCodeRequested found);
recovery = extract overlay from original CP/M media. Harness tools/mcdiff.sh:
stage 1 green (1a clean, 1b FORWARD-OK, 1d spot-check; fixed StrLenHelper,
word6, Doubles.proc5, Scanner.word2, Compiler.word3 leftovers on the way).
VM builds clean (gcc, `m2` binary); stage-2 run blocked on terminal I/O
(documented pty approach in mcdiff.sh header).
Next: GENZ80 media hunt; stage-2 pty-driven MCD diff per module.

## Next steps (in order)

1. DONE (`statemen-draft-v1`): `STATEMEN.MOD` 830 lines + frame-mechanics proof.
2. DONE (`pass1-draft-v1`): `PASS1.MOD` 981 lines; disputes D1-D4 + proc9 recorded.
2. Pass1 bodies (`pass1.txt`, 2975 lines): `~ParseType` (02e6), `ParseRecord`,
   formals, decls, module heads, `WriteSym` — 3–4 workers.
3. Resolve `SYMTAB.MOD` FIXMEs (AllocSym arity, D-group sketches, LSL) and
   `EXPRESS.MOD` FORWARDs (CentralError/PushOperand/EmitOp/BoolCondHelper/...).
4. `GENZ80` native backend (untouched so far).
5. Recompile + `unassemble.c` MCD diff verification for every draft.
6. Refresh `SUMMARY.md` + retag when milestones land.

## SCANNER verify checkpoint (2026-10-06, uncommitted -> committing)
- SCANNER.MOD compiles on v1.00 (2760 bytes): OOM cliff bisected to
  `FLOAT((decVal + LONG(1)) DIV LONG(2))` expression heap spike; fixed with
  `1L`/`2L` literal folding (identical codegen, proven T3d probe).
- MCD diff vs Reloaded SCANNER.MCD: 34/41 mnemonic-identical (00-gap
  stripped, absolute targets masked). Remaining 7 fully accounted:
  proc23/24 clean-room (hand-tuned M-stack code has no v1.00 source form;
  algorithms decoded + restored incl. c=TRUE fold branch the decompiler
  dropped), NUMBER 4-mn literal-fold trade (forced by OOM fix),
  proc37 tail = next-proc boundary attribution (35/35 prefix identical),
  COMPIL prologue = VarAddr shim `nested_call proc40` (module VarAddr
  exists nowhere; open-array shim proven), proc40 = original Z80 asmcode
  blob vs shim, proc0 = 2-op stub identical (rest is gap slack).
- StrLen signature now `(s: ADDRESS; bound: CARDINAL)` matching original
  DEF proc24 slots (WORD->CARDINAL: v1.00 WORD has no comparisons);
  SYMTAB.MOD:221 caller fixed to pass bound 128 (proven from symtab.txt
  `load immediate 128` at call site); CODEGEN.MOD:392 already 2-arg.
- Padding blocks removed (Allocate/FindIden/NextCh/ScanNext) — were dead
  code polluting the diff; GetSym now byte-compares modulo gap zeros.

## CODEGEN verify checkpoint (2026-10-12)
- CODEGEN.MOD compiles on v1.00 (2393 bytes): 34/37 mnemonic-identical.
- Stale renames fixed (codeBuf/EnterMod/ScanErr). keywordTable saga closed:
  original COMPILER.MOD also Allocate+CARDINAL-stores (proven byte-shape),
  CODEGEN reads low byte via `limit_check+shl1+LXB` = `compTab[i][0]` shape;
  v1.00 can't spell that from ADDRESS global, so local 2D-BYTE overlay
  (Q1/Q2-proven ADDRESS:=pointer assigns) at 2 use sites, +2mn each.
- proc0 trailing region = embedded absolute-address tables shifted by the
  +6 growth (every byte -4): consequential, not semantic.