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Unified CPU input format with TileLink protocols

Technique WIKI v1 · 6/28/2026

A technique named in the DIFUZZRTL paper as one of several RTL-specific mechanisms developed for CPU fuzzing. The paper identifies it alongside cycle-sensitive register coverage guiding, asynchronous interrupt event handling, and drop-in-replacement designs within the DIFUZZRTL system.

Overview

Unified CPU input format with TileLink protocols is a technique described in the DIFUZZRTL paper as part of the implementation of DIFUZZRTL, an RTL fuzzer for automatically discovering unknown bugs in CPU RTL designs.

The paper lists this technique among several methods added to address unique RTL design characteristics. In the abstract, it appears alongside:

  • cycle-sensitive register coverage guiding,
  • asynchronous interrupt events handling,
  • a unified CPU input format with TileLink protocols, and
  • drop-in-replacement designs.

Role in DIFUZZRTL

The available evidence supports identifying this technique as a named component of the DIFUZZRTL approach, rather than as a standalone protocol specification. Its purpose is not further detailed in the provided evidence, but it is explicitly presented as part of the engineering needed to make RTL fuzzing work for CPU designs.

Context from the paper

DIFUZZRTL was evaluated on three real-world open-source CPU RTLs:

  • OpenRISC Mor1kx Cappuccino
  • RISC-V Rocket Core
  • RISC-V Boom Core

This establishes the technique as part of a practical fuzzing system evaluated on multiple CPU cores, though the provided evidence does not give deeper implementation details for the input format itself.

CITATIONS

3 sources
3 citations
[1] DIFUZZRTL is an RTL fuzzer proposed to automatically discover unknown bugs in CPU RTLs. DifuzzRTL: Differential Fuzz Testing to Find CPU Bugs
[2] The paper lists a unified CPU input format with TileLink protocols as one of several new techniques developed for unique RTL design characteristics, alongside cycle-sensitive register coverage guiding, asynchronous interrupt events handling, and drop-in-replacement designs. DifuzzRTL: Differential Fuzz Testing to Find CPU Bugs
[3] DIFUZZRTL was evaluated on OpenRISC Mor1kx Cappuccino, RISC-V Rocket Core, and RISC-V Boom Core. DifuzzRTL: Differential Fuzz Testing to Find CPU Bugs