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Jennifer Taylor 86f54c495e Fix flake8 error. 2 years ago
arcadeutils Fix flake8 error. 2 years ago
.gitignore Update root support files. 2 years ago Include ROM utilities from Grid SRAM dumper project. 2 years ago
bindiff Add binary diffing utilities found in several of my repositories. 2 years ago
requirements.txt Make package installable on python systems. 2 years ago Make type hints in library accessible to mypy. 2 years ago
splitrom Include ROM utilities from Grid SRAM dumper project. 2 years ago


Collection of utilities written in Python for working with various arcade binaries. This is mostly suited towards the separated formats found in MAME archival releases but also work on a variety of binaries from basically anywhere.


Create a binary diff from two same-length binaries, or apply a previously created diff to a binary to patch that binary. Run it like ./bindiff diff --help to see options for diffing, and ./bindiff patch --help to see options for patching.

The patch format is simple. The number on the left of the colon is the hex offset where the difference was found, and the numbers on the right are the hex values to find and replace. A wildcard (*) can be substituted for a hex pair for any byte in the before section if you do not care what the value is, but be aware that this will make the patch non-reversible. Arbitrary comments are supported anywhere in the diff. Start a line with the # character to create a comment. Special values are recognized in comments. If you create a comment starting with # File size: then the the base file will be compared against the decimal number placed after the colon and any file not matching that length will be rejected.

Some examples are as follows:

A simple patch changing a byte in a file at offset 0x256 from 0xAA to 0xDD:

256: AA -> DD

That same patch, but only for files that are exactly 1024 bytes long:

# File size: 1024
256: AA -> DD

A patch that does not care about one of the bytes it is patching. The byte at 0x513 can be any value and the patch will still be applied, and altogether 4 bytes starting at 0x512 will be changed to the hex value 0x00 0x11 0x22 0x33:

512: AA * CC DD -> 00 11 22 33

A patch with multiple offsets, and helpful author descriptions for each section:

# This part of the patch fixes a sprite offset issue.
128: AA -> BB

# This part of the patch fixes sound playback issues.
256: 33 -> 44


Utility for combining/splitting/byteswapping ROM files. Run it like ./splitrom --help to see generic help and what commands are available, and like ./splitrom <command> --help for a specific command's help.