# maskromtool **Repository Path**: ynxing/maskromtool ## Basic Information - **Project Name**: maskromtool - **Description**: No description available - **Primary Language**: Unknown - **License**: Not specified - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2024-07-28 - **Last Updated**: 2024-07-28 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README Howdy y'all, This is my CAD tool for taking photographs of a mask ROMs and extracting the bits, so that the contents of the ROM can be recovered. The keyboard shortcuts in this tool are *not* optional. Please read the GUI documentation below before starting to explore. --Travis Goodspeed ![Screenshot of the tool.](screenshots/screenshot.png) ## Examples [gbrom-tutorial](https://github.com/travisgoodspeed/gbrom-tutorial) teaches you how to begin with photographs of the GameBoy's mask ROM and work your way to an accurate ROM image. [MYK82 ROM](https://github.com/travisgoodspeed/myk82rom) holds a completed dump of the ROM from the MYK82 chip in a Fortezza Card. This is the successor to the Clipper Chip, and the repository includes not just all ROM bits but also reshoots for error correction. [wersi-slm2-51173](https://github.com/travisgoodspeed/wersi-slm2-51173/) is a Zilog Z8 ROM from a music synthesize module. ## Release Changelog `master` -- Gatorom's solver-set option now uses descriptive fiilenames. GUI can now export a set of solved results with File/Export/SolverSetBytes. Clearer selection rectangle. `R` and `C` will now draw the correct line type when the user confuses them. `^H` now sets the home position. Zooming and movement keys now work in the second view. Perfectly duplicates lines are now culled during DRC by the `V` key. Rows and columns are now stored as sorted lists intead of sets. Rows and columns are now in a consistent order in the file export. 2024-07-14 -- Fixes crash when deleting a double-selected item. Delete and backspace now delete objects like `D`. Multiple disassemblers. Decodings are now updated as decoding thresholds are changed. 2024-06-23 -- Yara rule solving. Stability improvements. Crosshairs update to the angles of selected lines. Space now repeats the last line, whether row or column. Multiple items can be selected, and SHIFT+D duplicates them. Select with SHIFT to add more lines or CTRL (CMD on macOS) to remove lines. Right dragging moves multiple lines, previewing only relevant bits. Crosshair and selection colors are now selectable. Background is no longer tiled when zooming out. 2024-05-19 -- DRC violations are now cleared when bits are forced. Histogram export for ploting the color distributions in GNUPlot. Support for Wayland. Explicit wordsize support in CLI, GUI, solver and basic decoders. Solver sets, exporting all potential solutions as binary files. Unreliable aligner has been deprecated. GUI solver. Disassembler calls out to MAME's Unidasm. 2024-01-28 -- Undo and Redo. Strings dialog. Backslash key for layer visibility. Reliable alignment algorithm. Closing main window closes application. 2024-01-01 -- Fixes bus error in Z8 decoder when solving odd sizes. Verbose mode in the GatoROM CLI. `squeeze-lr` mode now in GUI decoder. Edit menu item to clear all bit fixes. `E` will select the next DRC violation. Perfectly vertical images no longer break the alignment algorithm. 2023-12-07 -- Selection highlight. Row/column counts in status bar. ASCII solver. Fixes multiple [crashes](https://github.com/travisgoodspeed/maskromtool/issues/59) in solver from awkward ROM sizes. GatoROM decoding in the GUI. Removal of redundant decoders. Hex viewer and highlighting of selected bytes. GatoROM CLI is now very strict about exiting on illegal access. [Zilog Z8](https://github.com/travisgoodspeed/maskromtool/issues/76) ROM support. 2023-09-13 -- CLI option to disable OpenGL. Printing support. Working Windows build. 2023-08-06 -- OpenGL is now functional and default. GatoROM included for bit decoding. 2023-07-20 -- Secondary display support. Tall sampling. Fixes crash when hitting `V` after deleting a line. 2023-06-17 -- Added macOS on X86_64 and ARM64. 2023-05-30 -- First Windows release. ## Building This tool works in Windows, Linux, FreeBSD and MacOS, using QT6 with the QtCharts extension. Building the tool is easiest from the CLI. In Debian Bullseye (11.x), ``` % sudo apt install make gcc g++ cmake git qt6-base-dev libqt6charts6-dev \ qt6-translations-l10n linguist-qt6 qt6-l10n-tools qt6-tools-\* qt6-image-formats-plugins % git clone https://github.com/travisgoodspeed/maskromtool/ ... % cd maskromtool % mkdir build; cd build % cmake .. % make -j 8 && sudo make install ``` In Windows and macOS, use the [Qt for Open Source](https://www.qt.io/download-qt-installer-oss) installer, being sure to include the Charts and Image Formats extensions. Then open `CMakeLists.txt` as a project. `Ctrl+B` will then compile `maskromtool`. If you have a problem with your import, such as choosing the wrong Qt installation, delete `CMakeLists.txt.user` and reopen the project to try again. For the convenience of Windows and macOS users, we have also made some [Prebuilt Releases](https://github.com/travisgoodspeed/maskromtool/releases). ## GUI Usage First use File/Open ROM to open a ROM image as a photograph. Try to use uncompressed formats, but beware that macOS doesn't like TIFF files. Holding the control key (command on macOS) while rolling the mouse wheel will zoom in and out. You can also pinch-zoom on a track pad. Dragging with the middle button will pan, or scroll with two fingers as your operating system likes. By arbitrary convention, the bits should be in long columns with shorter rows. If decoder lines are visible, they ought to be at the top of the image. Feel free to photograph it one way, then rotate it for markup. When you save your project, the image's filename will be extended with `.json`. This sorted and indented JSON file should be appropriate for use in version control, such as Git repositories. These keyboard buttons then provide most of your input. For drawing lines, first click once to choose as start position and then press the key when the mouse is above the end position. Deleting an item or Setting its position will apply to the most recently placed line, unless you drag a box to select a line. Select an item by dragging over it with a left mouse click and watching for it to turn green. The most recently placed item is automatically selected. Some commands work on multiple selected items; others just one. You can delete a mistake with `D` or adjust its position a little with `S`, the arrow keys, or a right-click drag. During movement the bits of unrelated lines might be hidden for performance, and the `M` key or releasing the right mouse button will redraw them. On macOS, `^` means Command instead of Ctrl. ``` Tab -- Show/Hide bits. \ -- Show/Hide rows and columns. ^\ -- Show/Hide background. ALT \ -- Show/Hide crosshair. R -- Draw a row from the last left-click position. SHIFT R -- Repeat the last row. C -- Draw a column from the last left-click position. SHIFT C -- Repeat the last column. SPACE -- Repeat the last row or column. D -- Delete the selected objects. SHIFT D -- Duplicate the selected lines. S -- Set the selected object to the mouse position. F -- Jump to the selected item. ARROWS -- Move the selected items. right-drag -- Move the selected items. (SHIFT or ^) middle-drag -- Pan the view. ^ wheel -- Zoom. Q -- Zoom to zero. A -- Zoom in. Z -- Zoom out. H -- Jump to home position. ^H -- Set the home position. SHIFT F -- Force a bit's value. (Again to flip.) SHIFT A -- Force a bit's ambiguity. (Again to flip.) M -- Remark all of the bits. SHIFT M -- Update hex decoding and disassembly. V -- Run the Design Rule Checks. SHIFT V -- Clear the DRC violations. E -- Jump to next violation. ^Z -- Undo SHIFT ^Z -- Redo ^S -- Save changes. ``` When you first begin to mark bits, the software won't yet know the threshold between a one and a zero. You can configure this with `View` / `Choose Bit Threshold`. Even the best bits won't all be perfectly marked, so use `SHIFT+F` to force bit values where you see that the software is wrong. `SHIFT+A` is similar, and marks a bit as being ambiguous or damaged. The `DRC` menu contains Design Rule Checks that will highlight problems in your project, such as weak bits or broken alignment. If placing many lines becomes tedious, select a group with your left mouse button and duplicate the entire set with `SHIFT+D`. You can then drag it with the right mouse button to the new position, leaving another copy in the original position. If the framerate drops for this, use the `TAB` key to temporarily hide all bits, which greatly speeds up moving many lines in dense areas. The crosshairs will adjust themselves to your most recently placed row and column. This should let them tilt a little to match the reality of your photographs. After you have marked the bits and spot checked that they are accurate with DRC, run File/Export to dump them into ASCII for parsing with other tools, such as [GatoROM](GATOREADME.md), [Bitviewer](https://github.com/SiliconAnalysis/bitviewer) or [ZorRom](https://github.com/SiliconAnalysis/zorrom). ## CLI Usage In addition to the GUI, this tool has a command line interface that can be useful in scripting. Use the `--help` switch to see the latest parameters, and the `--exit` switch if you'd prefer the GUI not stay open for interactive use. ``` forum% maskromtool --help Usage: maskromtool [options] image json Mask ROM Tool Options: -h, --help Displays help on commandline options. --help-all Displays help, including generic Qt options. -v, --version Displays version information. -V, --verbose Print verbose debugging messages. --stress Stress test bit marking. -e, --exit Exit after processing arguments. --disable-opengl Disable OpenGL. --enable-opengl Enable OpenGL. -d, --drc Run default Design Rule Checks. -D, --DRC Run all Design Rule Checks. --sampler Bit Sampling Algorithm. --diff-ascii Compares against ASCII art, for finding errors. -a, --export-ascii Export ASCII bits. -o, --export Export ROM bytes. --export-histogram Export histogram. --export-csv Export CSV bits for use in Matlab or Excel. --export-json Export JSON bit positions. --export-python Export Python arrays. --export-photo Export a photograph. Arguments: image ROM photograph to open. json JSON lines to open. ``` To run without a GUI, pass `-platform offscreen`. If the program crashes under Wayland, force Xorg usage by passing `-platform xcb`. On Windows, it's awkward for an executable to have a GUI while retaining a log on the CLI. We solve this by producing two executables; please use `maskromtool.exe` for the GUI and `maskromtoolcli.exe` for the CLI. A separate executable, `gatorom`, wraps the ROM bit decoder without the graphics. See [GatoROM](GATOREADME.md) for details. ``` forum% gatorom Usage: gatorom [options] bitstream Gato ROM: A Decoder for Mask ROM Bits Options: -h, --help Displays help on commandline options. --help-all Displays help, including generic Qt options. -v, --version Displays version information. -V, --verbose Talk too much. -w, --wordsize <8> Word size.bits -r, --rotate Rotates the image in multiples of 90 degrees. --flipx Flips the bits along the X axis. --flipy Flips the bits along the Y axis. -i, --invert Inverts the bits. -o, --output Output file. --random Randomize a ROM for testing. --Random Randomize a crazy ROM. --rawwidth, --seanriddle Width of a raw binary input, in Sean Riddle's style. -I, --info Info about input. -d, --dis Disassemble. --print Print with a GUI dialog. --printpdf Print to a PDF file. --decode-tlcs47font Decodes as a TMP47C434N Font. --decode-z86x1 Decodes as a Zilog Z86x1. --decode-cols-downl-swap Decodes as a uCOM4 ROM. --decode-cols-downr Decodes first down then right like a Gameboy. --decode-cols-downl Decodes first down then left. --decode-cols-left Decodes left-to-right. --decode-cols-right Decodes right-to-left. --decode-squeeze-lr Decodes even bits from the left, odd bits from right like in the TMS32C15. -z, --zorrom Zorrom compatibility mode, with flipx before rotation. --leftbank Only the left half of the bits. --rightbank Only the right half of the bits. -a, --print-bits Prints ASCII art of the transformed bits. -A, --print-pretty-bits Prints ASCII art with spaces. --solve Solves for an unknown format. --solve-bytes Bytes as a hint to the solver. 0:31,1:fe,2:ff --solve-ascii Look for ASCII strings. --solve-string Byte string as a hint to the solver. 31,fe,ff --solve-yara Yara rule file. --solve-set Exports all potential solutions. Arguments: bitstream ASCII art of ROM to decode. ``` ## High Level Design I've designed the GUI around a `QGraphicsScene`. The underlying data objects use the QT coordinate system, with floats for better-than-pixel precision. After loading a ROM photograph, the user places Columns and Rows onto the photograph. Every intersection of a Column and a Row is considered to be a Bit, and a configurable color threshold determines the value of that Bit. Where the photograph is misread, you can also Force the bit to a known value. Once all of the Bits have been marked and the Threshold chosen, the software will mark every light bit as Blue (0) and every dark bit as Red (1). These bits are then Aligned into linked lists of rows for export as ASCII, for use in other tools. To identify errors, a set of Design Rule Checks (DRC) will critique the open project. While the primary interface is the GUI, a CLI is also available for scripting and testing. ## Correcting Bit Errors While a few thousand bits might be marked without an error, larger projects will inevitably need to manage their mistakes. A good start is to use the DRC checks and careful configuration of the bit thresholds until no obvious errors remain. Then navigate the project and hit the `tab` key to show and hide the annotations, making sure that each bit is recognized properly. When that is insufficient, such as for ROMs that are tens or hundreds of kilobits, it helps to annotate the same ROM multiple times, preferably from different photographs. Bit errors will happen in annotating each photograph, of course, but they will happen in different places. You can then use the `--diff-ascii` feature against the output of `--export-ascii` to compare images, reconciling their differences until all of your project files agree. ## Sampling Algorithms Most ROMs can be read simply by reading the color of a single pixel at the bit's center. For those, the `Default` sampling algorithm will work just fine. ![Normal ROM Bits](screenshots/darkbits.png) For diffusion ROMs whose bits have been a little too delayered, the center of the bit does not have a unique color, but it is surrounded by slightly darker lines. The `Wide` algorithm will take the darkest color in each channel after sampling its size worth of bits in width, and `Tall` does the same but vertically. ![Diffusion ROM Bits](screenshots/diffusion.png) ## Development Patches and improvements to Mask ROM Tool are most welcome, but please do not spam the issue tracker with feature requests. Pull requests should be submitted through the Github page, and they should not entangle the project with dependencies upon third-party libraries. The code is written in a conservative dialect of C++, with minimal use of advanced features. I've tried to comment the code and the class definitions thoroughly. ## ROM Decoders [GatoROM](GATOREADME.md) is included as a command line decoder that solves for bit arrangements. Please see its own README file for CLI documentation, particularly for the solver methods that are not yet supported in the GUI. Separately, GatoROM is used as a library for decoding within the MaskRomTool GUI. Use Edit/Decoding to define the decoding style and View/HexPreview to see a live decoding of the bits to hexadecimal. ![Screenshot of MYK82 decoding.](screenshots/decoder.png) From the decoder, you can highlight hex bytes and use View/Highlight Hex Selection to visualize the selected bytes. Here we see the first three words of the [MYK82 ROM](https://github.com/travisgoodspeed/myk82rom), which pack 32 bits into each position. Disassembly is also available when `unidasm` from MAME is in the path. ![Screenshot of selected first three MYK82 words.](screenshots/selection.png) A scripted solver is also supported, in which simple masks or Yara rules describe the expected firmware. All matches are enumerated, and by jumping between them you can quickly decipher images that do not use interleving, row reversal, or other complications. ![Screenshot of the Yara solver.](screenshots/solver.png) ## Related Tools John McMaster's [ZorRom](https://github.com/SiliconAnalysis/zorrom) is an excellent decoder and the inspiration for the decoding library in this tool. Adam Laurie's [RomPar](https://github.com/AdamLaurie/rompar) might be the very first bit marking tool to be open sourced. Chris Gerlinsky's [Bitract](https://github.com/SiliconAnalysis/bitract/) is another open source tool for bit marking, and [Bitviewer](https://github.com/SiliconAnalysis/bitviewer) is his matching tool for decoding bits to bytes. Peter Bosch's [PLA Decode](https://github.com/peterbjornx/pladecode) is a bit marking tool used for extracting old Intel microcode. See his [Hardwear.io](https://www.youtube.com/watch?v=4oFOpDflJMA) talk from 2020 for more details.