DifuzzRTL is a differential fuzz testing framework specifically designed for CPU verification. It introduces a novel coverage metric called register-coverage to comprehensively capture RTL design states and guide input generation, then cross-checks results against an ISA simulator to detect bugs.

Key Features

• Register-Coverage Metric — A new coverage approach that comprehensively captures RTL design states to guide fuzzing input generation
• Differential Testing — Cross-checks RTL simulation results against an ISA simulator to identify discrepancies and bugs
• Automatic Instrumentation — Automatically instruments register-coverage into target RTL designs
• Instruction Mutation — Randomly generates and mutates instructions defined in the ISA for comprehensive testing
• CPU Bug Detection — Specifically designed to find bugs in CPU implementations through systematic fuzzing

Philosophy

DifuzzRTL takes a differential approach to CPU verification, combining coverage-guided fuzzing with cross-checking against reference models to systematically uncover bugs in RTL implementations.