X-Propagation and Reset Verification with Formal: Step-by-Step Walkthrough

Step-by-step analysis walkthrough

Use this sequence when owning X-Propagation and Reset Verification with Formal in a formal review.

1. Confirm trigger reachability and non-vacuous evaluation.

2. Inspect first-cycle divergence and classify failure source.

3. Check reset/fairness/assumption interactions before editing RTL.

4. Apply smallest reversible fix in model or implementation.

5. Re-run sibling properties and cover goals for collateral impact.

6. Archive decision with owner and residual-risk statement.

Artifacts to collect

• formal closure packet: assumptions audit, proof status matrix, counterexample classification, and requirement traceability

• counterexample replay package

• assumption traceability matrix

• vacuity and cover dashboard snapshot

• post-fix closure trend report

Decision memo template

FORMAL DECISION MEMO - X-Propagation and Reset Verification with Formal
symptom:
classification:
root cause:
fix:
validation:
owners: formal verification owner, rtl owner, verification lead

Formal deep dive

Formal apps generate high confidence when app-specific assumptions mirror integration and firmware behavior.

Concept diagram

FORMAL APPS MAP

connectivity + csr + progress + reset/x checks -> integrated SoC confidence

Metric graph

APPS CLOSURE QUALITY

functional app closure   ███████
environment realism      █████
waiver pressure          ███

Metrics and artifacts to collect

• connectivity route reachability

• CSR semantic correctness matrix

• progress guarantee closure by interface

• reset/X convergence confidence

Mini case study

Deadlock traces were resolved by tightening fairness assumptions to architecture contracts, not by weakening liveness guarantees.

Debug branches

• Validate mode and configuration constraints for each app.

• Pair safety and liveness checks for progress-sensitive logic.

• Add first-transaction covers for reset-sensitive interfaces.

Senior review question

Ask: which requirement intent is proven, under which assumptions, and what residual risk remains?

Key takeaways

• Tie each proof claim to assumption boundaries and reachability evidence.

• Prefer minimal reversible fixes and preserve legal behavior visibility.

Common pitfalls

• Treating runtime reduction as proof-quality improvement without audits.

• Declaring closure while critical covers remain unreachable.

• Using broad waivers instead of first-divergence root-cause ownership.

Principal formal review addendum

X-Propagation and Reset Verification with Formal should be reviewed as a requirement-evidence workflow, not a single status report.

Use non-vacuous closure rate, counterexample turnaround time, and requirement-level residual risk trend as the monitoring lens and formal closure packet: assumptions audit, proof status matrix, counterexample classification, and requirement traceability as closure proof.

Formal apps deliver high leverage when properties mirror system contracts: connectivity, access control, progress, and reset determinism. Strong teams preserve legal reachability while improving convergence.