Overview
Drop-in-replacement designs are identified in the DifuzzRTL: Differential Fuzz Testing to Find CPU Bugs paper as one of several techniques added to DIFUZZRTL to address the unique characteristics of CPU RTL fuzzing.
Role in DIFUZZRTL
The provided evidence states that DIFUZZRTL is an RTL fuzzer for automatically finding unknown bugs in CPU RTL designs. Within that contribution list, the paper specifically says DIFUZZRTL develops drop-in-replacement designs to support various CPU RTLs.
In the abstract, this technique is presented alongside other RTL-oriented mechanisms, including:
- cycle-sensitive register coverage guiding
- asynchronous interrupt event handling
- a unified CPU input format with Tilelink protocols
Supported characterization from the evidence
Based on the available source, the supported description of this technique is limited but clear:
- it is part of the DIFUZZRTL approach;
- it is intended to improve support across different CPU RTL implementations; and
- it is discussed as an RTL-specific design adaptation rather than as a standalone fuzzing method.
The provided abstract does not explain the internal structure, API shape, or integration mechanics of the drop-in-replacement designs, so those details cannot be stated here from the current evidence alone.