# V3 step 1 — minimal integer pipeline (done 2026-09-19)

End-to-end: Modula-2 source → Coco/R frontend → SymTab checks →
fresh QbeGen → `gen_ssa/<Mod>.ssa` → `qbe` → `cc` → native binary
returning `ExitCode`. Blaise Phase-1 equivalent (bootstrap pipeline).

## Subset

`MODULE` + `CONST` (signed literal) + `VAR .. : INTEGER` +
assignment + integer expressions (`+ - * DIV MOD`, leading sign,
parens, `H` hex). Errors: 200/201/202/210/211/221 + step-1 230s
(REAL/STRING literals, non-INTEGER VAR type, non-literal CONST,
imported names as values). Grammar is LL(1)-clean
(`Compilation completed. No errors detected.`); one conflict found
and fixed during the step (trailing `;` in StatSeq).

## Files

- `compiler/src/M2.atg` (fresh, ~250 lines) — the interactive artefact.
- `compiler/src/QbeGen.def/.mod` (fresh) — Test2-compatible signatures
  (`LoadVar/StoreVar/Op3/NegQ` keep `isReal` params) so step 2 grows
  without ATG rewrites. Deterministic `%tN` counters (fixpoint-safe).
- Reused proven: `FileIO`, `SymTab` (full Test2 copies),
  `scanner/parser/compiler.frm` (230 text retargeted to step 1).
- `compiler/build.sh`, `compiler/run_tests.sh`, 5 tests.

## Results — 5/5

3 run (`t_minimal`→0, `t_exit`→7, `t_arith`→25: precedence, DIV
truncation, hex `10H`=16, CONST loads) + 2 reject (201 undeclared,
202 name mismatch). Verified `TArith.ssa` by hand.

## Known step-1 limits (each a later step)

- Assignment targets emit a dead load before the store (valid QBE,
  inherited Test2 inefficiency).
- `DIV`/`MOD` are truncating (C/QBE semantics, not Modula-2 floor).
- No `TYPE`, no procedures, no composites, no `U`-literals —
  all syntax errors today, 230s where tokens exist (real/string).
- `gen_ssa/` binaries/logs are build outputs (gitignored).

Next: step 2 (scalar type system: REAL/BOOLEAN/CHAR/enum, relations,
`IF/WHILE`) reusing the same harness.