DeACC is a bytecode disassembler for Hexen and ZDoom ACS. Currently it mostly works, but may produce incorrect results in some cases due to incorrect data on opcodes and functions. File an issue if something's awry.
Automatic builds are available for Windows, Linux, and macOS - go to the CI jobs page and download the artefacts from the publish job for your platform. Alternatively, you can build DeACC yourself; the .NET 8.0 SDK is required.
To disassemble an ACS object file, open a terminal/command prompt, change to the directory you downloaded the executable to, and run the command below.
Replace path_to_input.o with your the object file you want to disassemble, and path_to_output.bcs with the file you want the disassembly to be written to.
DeACC disassemble -o path_to_output.bcs path_to_input.o
If building DeACC yourself from source, you can also do:
dotnet run --project DeACC\DeACC.csproj disassemble -o path_to_output.bcs path_to_input.o