The BatteryMonitor LLFSM

This repository contains the example machines discussed within the paper titled "Efficient Runtime Verification of Energy Properties within Hardware / Software Co-Design" presented at Aeroconf 2025.

The files contained within this repository define the BatteryMonitor LLFSM and the accompanying formal verification using Computation Tree Logic (CTL). The files of interest are contained within the structure below.

shell ├── BatteryMonitor.machine │   ├── data.dat │   ├── model.json │   ├── output.json │   └── spec.tctl └── img

• The data.dat file contains the binary-encoded Kripke structure transferred from the FPGA.
• The model.json file contains the machine definition which is consumed by our code generator to generate the respective VHDL files.
• The output.json file contains the parsed Kripke structure after it has been decoded from the binary representation within data.dat. This format is defined within this repository.
• The spec.tctl file contains the CTL formulae for defining the requirements formally verified using our model checker. The format of this file is defined within our CTL parser.
• The img directory contains image files of the Kripke structure in various formats generated from graphviz. You may open these files to see the full Kripke structure of the BatteryMonitor LLFSM. Please note that these files do not include the energy-labelled edges within the Kripke structure.

Installing the LLFSM Tools

If you would like to generate the VHDL source files or perform the formal verification yourself, you may do so from the command-line tools we provide. Please install the llfsmgenerate and llfsm-verify binaries onto your system. You will need to compile these programs from source using the Swift compiler.

Generating the VHDL source files

To generate the VHDL source files for this machine, you first need to invoke some preliminary steps using the llfsmgenerate binary.

shell llfsmgenerate model BatteryMonitor.machine

You then have a choice of generating the VHDL for Kripke structure generation, or just the standard VHDL sources for the machine.

Kripke Structure Program

shell llfsmgenerate vhdl --include-kripke-structure BatteryMonitor.machine

Standalone LLFSM

shell llfsmgenerate vhdl BatteryMonitor.machine

Your generated .vhd files will be located within BatteryMonitor.machine/build/vhdl.

Performing the Formal Verification

Performing the formal verification is as simple as invoking the llfsm-verify binary.

shell llfsm-verify --machine BatteryMonitor.machine BatteryMonitor.machine/spec.tctl

You will then see the output from the model checker satisfying the requirements.

``` Verifying Requirement (1/3): A G battery = "000" -> {A F mode = "00"}_{t <= 2 us} Finished Requirement 1 in 0.029007014 seconds.

Verifying Requirement (2/3): A G mode = "00" -> A mode = "00" W battery /= "000" Finished Requirement 2 in 0.028276522 seconds.

Verifying Requirement (3/3): A G mode = "00" -> E mode = "00" U battery /= "000" Finished Requirement 3 in 0.044123716 seconds.

Verification completed in 0.106220544 seconds (± 1e-09 seconds). ```

You may modify spec.tctl to include additional requirements of your choosing.