Lec 50: RTL to C Reverse Engineering

Item: Lec 50: RTL to C Reverse Engineering
Rating: 4
Author: PostSingularity Institute

by Prof. Chandan Karfa · View the channel on PSI

Formal & Physical Sciences Computing & Cybersecurity UYComputer science UYFComputer architecture and logic design

🎙 Prof. Chandan Karfa 👥 229K 📅 September 17, 2026 ⏱ 21 min 👁 1 📄 science communication 🧭 2026-09-17

Available in: English (current) Français

Keywords

RTLCFSMDEquivalence checkingCycle-accurate simulationData path

Summary

The lecture introduces a methodology to reverse engineer register transfer level (RTL) designs into an equivalent C description (called RTLC) to enable faster simulation and formal equivalence checking. The motivation is that RTL simulation is extremely slow (up to 34,000 seconds for some benchmarks) while C simulation takes only a few seconds (e.g., 28 seconds), yielding a speedup of over 300x. The core idea exploits the separable datapath and controller structure typical of HLS-generated RTL: by analyzing the control signals in each clock cycle, the operations executed in the datapath can be identified and abstracted into a finite state machine with datapath (FSMD), which is then converted to a C switch-case representation. The lecture addresses several challenges: handling Verilog concatenation and part-select operations via masking and shifting, mapping RAM/ROM instances to C arrays, converting module instantiations to function calls, resolving data inconsistencies caused by parallel execution (e.g., using old-value renaming), managing sign and data width mismatches, and dealing with loop unrolling and pipelining. The resulting RTLC is cycle-accurate, meaning it reproduces the exact clock-level behavior of the RTL, and supports fast simulation and integration into C-to-RTL equivalence checking workflows. Experimental results on large benchmarks demonstrate the tool’s efficiency and correctness.

200 words

Critical Evaluation

Value of the Information & Strength of the Argument

The value of the presented approach is twofold: it provides significant simulation speedups, which are critical for verifying large hardware designs, and it enables effective C-to-RTL equivalence checking, a key requirement for high-level synthesis. The argumentation is solid and well-structured: the speaker begins with the motivation, then explains the core methodology step by step, and addresses non-trivial practical issues with concrete examples. The claims are substantiated with quantitative results (speedups, cycle accuracy) and by referencing a peer-reviewed publication. The logical flow from problem statement to solution is clear, and the challenges are presented honestly, reinforcing the credibility of the method.

Scientific Rigor, Source Quality, Title Accuracy

The lecture demonstrates strong scientific rigor: it is grounded in a formal method (reverse engineering via symbolic rewriting) and aligns with established verification practices. The speaker references his own paper (published in TAR in 2022, though the exact venue abbreviation is unclear) as the basis for the technique. While no external sources are explicitly cited, the NPTEL course and playlist links are provided in the description, serving as additional resources. The title precisely matches the content, which is entirely dedicated to RTL-to-C reverse engineering, and does not exaggerate or mislead.

205 words

Title / Content Match

The title accurately describes the content, which focuses on reverse engineering RTL designs into C code for simulation and equivalence checking.

Quality & Reliability

9/10

The lecture is presented by a professor from IIT Guwahati, based on a peer-reviewed publication, with rigorous technical depth, clear explanations, and experimental results. The methodology is well-supported and the claims are backed by simulation data.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Formal Methods for System Verification (NPTEL Course) — Course page providing context and prerequisites for the lecture.
Course Playlist — Playlist containing related lectures on formal methods.

Contribution & Novelties

This lecture contributes a concrete methodology for generating C code from RTL that is cycle-accurate and supports efficient simulation and verification. It addresses numerous practical challenges in translating hardware constructs to software semantics, which is not trivial. The approach leverages a symbolic rewriting technique to extract operations from control signals, and demonstrates significant performance gains.

Pour aller plus loin :

Register-transfer level (RTL) — Provides background on the hardware abstraction level targeted by this work.
High-level synthesis (HLS) — Explains the process that generates RTL from C, the counterpart of the discussed reverse engineering.
Formal verification — Contextualizes the equivalence checking application mentioned in the lecture.

106 words

Radar Profile

The profile is highly skewed towards technical depth and information quality, with moderate breadth of content but strong methodological rigor. The video is ideal for advanced practitioners in hardware verification, offering both conceptual and practical insights.

Reliability 9/10