6502bench

Features - Getting Started - About the Code

6502bench is a code development "workbench" for 6502, 65C02, and 65802/65816 code. It currently features one tool, the SourceGen disassembler.

You can download the source code and build it yourself, or click the "Releases" tab for pre-built downloads.

SourceGen

SourceGen converts machine-language programs to assembly-language source code. It has most of the features you will find in other 6502 disassemblers, as well as many less-common ones.

Key Features

• Fully interactive point-and-click GUI. Define labels, set addresses, add comments, and see the results immediately. Add multi-line comments and have them word-wrapped automatically.
• The disassembly engine traces code execution, automatically finding all instructions reachable from a given starting point. Changes to the processor status flags are tracked, allowing identification of branches that are always/never taken, accurate cycle count listings, and correct analysis of 65816 code with variable-width registers.
• Easy generation of assembly source code in populate formats (currently cc65 and Merlin 32). Cross-assemblers can be invoked from the GUI to verify correctness.
• Symbols and constants are provided for ROM and operating system entry points on several popular systems.

A demo video is available on YouTube.

Additional Features

Analyzer:

• Support for 6502, 65C02, and 65816, including undocumented opcodes.
• Hinting mechanism allows manual identification of code, data, and inline data.
• Editable labels are generated for every branch destination and data target.
• Automatic detection and classification of ASCII strings and runs of identical bytes.
• Symbol files for ROM entry points, operating system constants, and other platform-specific data are stored in plain text files.
• Extension scripts can be defined that automatically reformat code and identify inline data that follows a JSR/JSL.

User interface:

• "Infinite" undo/redo of all operations.
• Cross-reference tables are generated for every branch and data target address, as well as for external platform symbols.
• Instruction operand formats (hex, decimal, binary, ASCII, symbol) can be set for individual instructions. References to nearby symbols are offset, allowing simple expressions like "addr + 1".
• Data areas can be formatted in various formats, including individual bytes, 16-bit and 24-bit words, addresses, or strings.
• Multi-line comments can be "boxed" for an authentic retro feel.
• Notes can be added that aren't included in generated output. These also function as color-coded bookmarks. Very useful for marking up a work in progress.
• Instruction summaries, including CPU cycles and flags modified, are shown along with a description of the opcode's function.
• Various aspects of the code display can be reconfigured, including upper/lower case, pseudo-opcode naming, and expression formats. These choices are not part of the project definition, so everyone can view a project according to their own personal preferences.

Code generation:

• Labels can be coaxed from global to local as allowed by the assembler.
• Symbols may be exported from one project and imported into another to facilitate multi-binary disassembly.

Miscellaneous:

• All data files are stored in text formats (primarly JSON).
• The project file includes nothing from the data file but a CRC. This may allow the project to be shared without violating copyrights (subject to local laws).

There are a couple of significant areas where support is currently lacking:

• Poor support for multi-bank 65816 files (IIgs OMF, SNES).
• No support for alternate character sets (e.g. PETSCII).

Getting Started

The best way to get started is by working through the tutorial. Launch SourceGen, hit F1 to open the user manual in your web browser, then scroll down near the bottom of the index page. Click on "Tutorials", and follow the instructions.

The tutorial is one of several examples included in the SourceGen distribution. The other directories contain project and data files for completed disassembly projects alongside the original source code, allowing a direct comparison between how the code was written and how SourceGen can display it.

About the Code

All of the code is written in C# .NET, using the (free to download) Visual Studio Community 2017 IDE as the primary development environment. The user interface uses the WinForms API. Efforts have been made to avoid doing anything Windows-specific, in the hope that the applications will be straightforward to port to other platforms.

The solution is called "WorkBench.sln" rather than "6502bench.sln" because some things in Visual Studio got weird when it didn't start with a letter.

The code style is closer to what Android uses than "standard" C#. Lines are folded to fit 100 columns.

The source code is licensed under Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0), which makes it free for use in both open-source programs and closed-source commercial software. The license terms are similar to BSD or MIT, but with some additional constraints on patent licensing. (This is the same license Google uses for the Android Open Source Project.)

Images are licensed under Creative Commons ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/).