HSP Decompiler (deHSP)

Converts HSP (Hot Soup Processor) 2 and 3 compiled files back to source code. Accepts .ax, .exe, and .dpm files and produces .hsp or .as output.

Features

• Decompiles HSP3 (.ax → .hsp) and HSP2 (.ax → .as) compiled files
• Extracts files from DPM archives
• Extracts DPM from HSP executables (.exe)
• Decrypts encrypted files in DPM archives (brute-force XOR+ADD)
• Cross-platform: Windows, macOS, Linux
• CLI tool and GUI application

Requirements

• .NET 8.0 SDK or later

Building

dotnet build HspDecompiler.sln

Usage

CLI

# Decompile an .ax file
dotnet run --project src/HspDecompiler.Cli -- input.ax

# Decompile with output directory
dotnet run --project src/HspDecompiler.Cli -- input.ax -o ./output

# Extract DPM archive
dotnet run --project src/HspDecompiler.Cli -- archive.dpm -o ./extracted

# Extract from HSP executable
dotnet run --project src/HspDecompiler.Cli -- game.exe -o ./extracted

Options:

dehsp <input-file> [options]
  -o, --output <dir>       Output directory (default: input file's directory)
  -d, --dictionary <path>  Dictionary.csv path (default: alongside executable)
  --no-decrypt             Skip encrypted file decryption
  --skip-encrypted         Extract only non-encrypted files from DPM
  -v, --verbose            Verbose logging
  --version                Show version
  -h, --help               Show help

GUI

dotnet run --project src/HspDecompiler.Gui

Or drag-and-drop files onto the application window.

Project Structure

Project	Description
HspDecompiler.Core	Core decompiler library — all algorithms
HspDecompiler.Cli	Command-line interface
HspDecompiler.Gui	Avalonia cross-platform GUI

Dictionary.csv

Dictionary.csv must be present alongside the executable. It defines HSP3 built-in commands, functions, and parameter types used during decompilation.

History

Date	Name	Version	Notes
2006-01-28	HSP Decompiler (HSP逆コンパイラ)	1.0	Initially released as shareware by Kitsutsuki
2007-09-10	HSP Decompiler	1.1	HSP3 support added
2010-09-12	HSP Decompiler	1.2	Released as PDS/OSS; bug fixes
2012-01-13	HSPdeco	1.0	.ax decode feature exposed; bug fixes. Author: minorshift (Mia)
2015-12-15	HSPdecom	1.0	Variable name restoration, dictionary data. Authors: Sitapuru, YSRKEN
2016-08-16	HSPdecom	1.1	Decryption patches applied; republished on GitHub
2026-03-13	deHSP	2.0	.NET 8.0 + Avalonia; CLI tool; cross-platform

License

PDS (Public Domain Software) for the HSPdecom parts. HSPdeco parts under zlib/libpng license. See the LICENSE file for details.