AgentSkillsCN

formal-verification

具备FPGA设计的形式化属性验证与模型检查能力，为设计的正确性与可靠性提供有力保障。

SKILL.md
--- frontmatter
name: formal-verification
description: Formal property verification and model checking skill for FPGA designs
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Formal Verification Skill

Overview

Expert skill for formal property verification and model checking, enabling exhaustive verification of FPGA design properties without simulation.

Capabilities

  • •Write properties for formal verification
  • •Configure formal tool constraints
  • •Analyze formal counterexamples
  • •Apply bounded model checking
  • •Configure cover and assume directives
  • •Debug formal failures
  • •Integrate formal with simulation flows
  • •Support JasperGold and VC Formal flows

Target Processes

  • •sva-development.js
  • •cdc-design.js
  • •constrained-random-verification.js

Usage Guidelines

Property Types

  • •assert property: Must always hold
  • •assume property: Environment constraints
  • •cover property: Reachability goals
  • •restrict property: Strong constraints

Formal Approaches

  • •Bounded Model Checking: Check properties up to N cycles
  • •Unbounded Proof: Complete verification when possible
  • •Induction: K-induction for liveness properties
  • •Abstraction: Reduce complexity for scalability

Writing Effective Properties

systemverilog
// Safety property
assert property (@(posedge clk) disable iff (rst)
  req |-> ##[1:5] gnt);

// Liveness property (bounded)
assert property (@(posedge clk) disable iff (rst)
  req |-> s_eventually gnt);

// Assumption for formal
assume property (@(posedge clk)
  $onehot0(req_vec));

Constraint Development

  • •Model input protocol constraints
  • •Constrain unrealistic scenarios
  • •Avoid over-constraining
  • •Use helper logic for complex constraints
  • •Document constraint rationale

Counterexample Analysis

  • •Load counterexample trace
  • •Identify root cause
  • •Distinguish bug vs. missing constraint
  • •Create regression test from counterexample
  • •Update constraints or fix RTL

Tool Integration

  • •Configure engine selection
  • •Set proof bounds appropriately
  • •Use proof acceleration techniques
  • •Integrate with regression flows
  • •Archive proof results

Dependencies

  • •Formal tool awareness (JasperGold, VC Formal)
  • •SVA expertise
  • •Model checking theory knowledge