hatariB

A Libretro core integrating the Hatari emulation of Atari ST, STE, TT, and Falcon computers.

• Current Build Platforms:
  • Windows 64-bit, 32-bit
  • Ubuntu
  • MacOS 11.0 Apple Arm, 10.13 Intel 64-bit
  • Raspberry Pi OS 64-bit, 32-bit
  • Android 64-bit, 32-bit
• Current Release:
  • hatariB v0.3 - 2024-04-15
• Unstable Build:
  • Download
• Recent Builds:
  • Github Actions

Other platforms may be possible. See Manual Build below.

This is intended as an alternative or replacement for the older Libretro Hatari Core.

This is a new project in the initial testing phase. Eventually I would like to submit it to Libretro.

If you notice any problems or have feedback, please create a Github issue. If you can, test in Hatari's stand-alone emulator first to see if the problem exists there as well.

Emulator: Hatari 2.5.0 2024-04-18

Development notes: DEVELOP.md

Table of Contents

• Installation
  • MacOS
  • Android
  • Manual Build
• Notes
  • Hatari Manual
  • Controls
  • File formats
  • Hard Disks
  • M3U playlists and Auto-Run
  • On-Screen Keyboard
  • Savestates
  • Netplay
  • Unsupported Features
  • Quirks
• History
• License
• Authors

Installation

The build artifact ZIP files contain a core/ and info/ folder. The core folder contains the hatariB core object, and the info folder contains metadata that allows RetroArch to know its associated file types.

On Windows, if using RetroArch's portable Download version instead of the installer, you can simply copy the core and info files into the RetroArch folder and it will merge into those folders. If installed, or on other platforms, you may need to locate the needed core and info folders. You can find these in RetroArch's Settings > Directories menu under Cores and Core Info. Similarly the system/ folder referred to below where you can place your TOS and hard disk image files is actually the RetroArch System/BIOS directory.

Depending on the platform, you may also need to add executable permission to the core file (e.g. chmod +x hatarib.so). See below for MacOS instructions.

For IPF and CTR floppy disk image support, you will also need to provide the capsimg 5.1 support library, originally created by the Software Preservation Society. This library will be a file named capsimg.dll or capsimg.so, depending on your platform. On Windows this DLL should be placed in your RetroArch installation folder next to retroarch.exe. On other platforms it must be installed in your search path for dlopen, so if it isn't found next to the SO, maybe try /usr/lib? An up to date version of capsimg for many platforms can be downloaded here:

• capsimg 5.1 binaries

If you have trouble getting the builds to work, you can turn on logging under Settings > Logging. Log output to a file, restart RetoArch, then try to start the core. After it fails, close RetroArch and find the log. There should hopefully be an error message near the bottom of the log, which might help if we're not unlucky.

MacOS

Installing for MacOS requires a different method for giving permission:

• On older versions of MacOS, you may be able to right click (or ctrl+click) on cores/hatarib.dylib and open it, after which you can give it permission to run.
• On newer versions, you may have to remove a download quarantine:
  • Open the Terminal utility, navigate to the folder where hatarib.dylib was extracted.
  • Type: xattr -d com.apple.quarantine hatarib.dylib
  • Type: chmod +x hatarib.dylib
  • To make it easier, instead of navigating to the directory, instead of typing hatarib.dylib you can drag it into the terminal window, which will automatically paste its full path there.

Once the file is un-quarantined, and given permission to execute, you can copy it to your RetroArch cores folder.

• On MacOS the cores and info folders are usually at: Users/[username]/Library/Application Support/RetroArch.

The capsimg.so for IPF support can be placed next to the hatarib.dylib file, but it must also be given permission in the same way.

Android

You can use this core with the latest RetroArch APK, or with the older RetroArch Plus build from the Google Play store.

• After setting up RetroArch, place hatarib.so in your RetroArch downloads folder. You can use the Directory settings to find it, or choose a custom downloads location. Go to Load Core and choose Install or Restore a Core to install it from the downloads folder. If installed correctly, you should now be able to load it and start it.
• The included hatarib.info file allows the core to be associated with content files, but it can be inconvenient to add this to your RetroArch setup. The easiest alternative is to rename the core to hatari_libretro.so before installing so that it will instead use the existing info file belonging to the other Hatari core.
• If you want to be more thorough, use the Directory settings to relocate Core Info to a folder that you can access and place it there. However, I've found that Update Core Info Files in the Online Updater doesn't work with a custom directory, so I had to manually download and place the info files for other cores there. If you rename the RetroArch APK to be a zip file, you can open it up and find the info files there inside the contained assets folder.
• To delete the core, you can go to Core > Manage Cores in the settings.
• It is not yet verified whether IPF files can be made to work by installing capsimg.so. I believe the way to do this would be to build your own RetroArch APK from source code, and include it in the lib folder inside, but I have not attempted this. It might also be possible to do this after install with a rooted device. Please let me know if you've tried it.
• I would recommend disabling Input > Host Mouse Enabled in the core options, as using a touchscreen overlay gamepad will also generate host mouse inputs at the same time. Retropad 1 > Left Analog Stick can be set to Mouse to allow mouse control that way instead.

Manual Build

If you want to try building it yourself, in theory it should build on any platform supported by SDL2.

Prerequisite tools: git, make, cmake, gcc.

Open a terminal to the directory you want to use, and do the following:

• git clone https://github.com/bbbradsmith/hatariB.git
• cd hatariB
• make full

If successful, this should create hatariB/build/hatarib.so (or DLL/dylib).

If unsuccessful, you might look at build.yml which runs the Github Actions builds for ideas.

If unsuccessful because the system is out of memory (may look like a "fatal error" of GCC), try setting the MULTITHREAD variable to empty:

• make full MULTITHREAD=

By default all warnings are enabled and treated as werrors. If unsuccessful because of spurious warnings, try setting the WERROR variable to empty:

• make full WERROR=

See DEVELOP.md for more details.

Notes

Hatari Manual

• Hatari Online Manual

Controls

• Left Stick and D-Pad - Joystick
• Right Stick - Mouse
• B - Joystick Fire
• A - Joystick Autofire
• Y, X - Mouse Left, Right
• Select - Select drive A or B
• Start - Help screen
• L1 - On-screen keyboard
• R1 - On-screen keyboard one-shot
• L2, R2 - Mouse Slow, Fast
• L3 - Space key
• R3 - Return key
• On-screen keyboard
  • L1 - Confirm
  • R1 - Cancel
  • X - Toggle Position
• RetroArch
  • Scroll-Lock - Game Focus mode captures mouse, and full host keyboard input.
  • F11 - Captures or releases the mouse.
• Keyboard
  • Atari ST special keys (Your Key -> Atari Key)
    • F11 -> Home
    • F12, End -> Undo
    • Page Up -> Numpad (
    • Page Down -> Numpad )
  • Other keys map directly to a standard keyboard, but Game Focus mode (Scroll-Lock) may be neeed to access keys normally assigned to RetroArch hotkeys.
• Gamepad buttons can be reassigned in the Retropad core options:
  • None - To disable the button.
  • Fire - Joystick fire.
  • Auto-Fire - Automatically repeating joystick fire.
  • Mouse Left/Right - Mouse buttons.
  • On-Screen Keyboard - Raises the on-screen keyboard.
  • On-Screen Keyboard One-Shot - Pauses emulation and raises the on-screen keyboard. Resumes when you confirm/cancel a keypress.
  • Select Floppy Drive - Selects drive A or B to use with the Libretro disk controls.
  • Swap to Next Disk - Ejects the disk in the selected drive and inserts the next one.
  • Help Screen / Pause - Pauses emulation and brings up a help screen or other display. You can choose a pause display under Video > Pause Screen Display.
  • Joystick Up - For those who don't like up-to-jump controls, you can make it a button.
  • Joystick Down/Left/Right - The other joystick directions can be made into buttons too.
  • STE Button A/B/C/Option/Pause - Buttons for the enhanced STE controller ports.
  • Mouse Speed Slow/Fast - Hold to slow or speed the mouse, useful if you have no analog stick.
  • Soft/Hard Reset - If you need a button to reset the machine.
  • CPU Speed - Switches between 8 MHz, 16 MHz, and 32 MHz CPU speeds.
  • Toggle Status Bar - A quick hide/reveal of the status bar, in case you like it hidden but still want to check it sometimes.
  • Joystick / Mouse Toggle - Temporarily swaps stick/d-pad assigned to Joystick to Mouse, and vice versa. Also swaps the joystick fire button for mouse left.
  • Key Space/Return/Up/Down... - Any keyboard key can be assigned to a button.
• The help screen mapped to Start can be configured to display other information, such as the floppy disk list. See Video > Pause Screen Display in the core options.

File formats

• Floppy disk: ST, MSA, DIM, STX, IPF, CTR (can be inside ZIP/ZST or GZ)
• Hard disk: ACSI, AHD, VHD, SCSI, SHD, IDE, GEM
• Muli-disk: M3U, M3U8, ZIP, ZST
• TOS ROM: TOS, IMG, ROM, BIN
• Cartridge: IMG, ROM, BIN, CART
• TOS, Cartridge, and permanent Hard disk files should be placed in system/hatarib/.
• When loading multiple disks, the best method is to use M3U playlists to specify all needed disks at once during Load Content. This can also include temporary hard disk images. Information: M3U file tutorial.
• ZIP files will load all contained disk images, but if there is an M3U or M3U8 file it will be used to index and load images from the ZIP. Hard disk images cannot be used from inside a ZIP. Only one M3U can be used from inside a ZIP.
• ZST is a renamed ZIP file. It does the same thing as the ZIP but the alternate extension lets you skip the "Load Archive" menu.
• GZ is a single file compressed in the gzip format. It can be used to contain any of the floppy disk formats.
• Load New Disk can add additional disks while running, but has several caveats, especially regarding savestates. See Savestates section below.
• The first two disks of an M3U list will be loaded into drive A and B at startup, but this can be overridden with #BOOTA or #BOOTB, see M3U notes below.
• Libretro only has an interface for one disk drive, but you can use the Select button to switch between whether the Disc Control menu currently shows drive A or drive B.
• IPF and CTR formats are only available with the addition of the capsimg support libraray. See Installation for more information.

Hard Disks

• A permanent hard disk in your system/ folder can be configured from the System core options menu, but this setting can be overridden by a temporary hard disk loaded from the content menu, or using an M3U playlist.
• GemDOS type hard disks can select a subdirectory within system/hatarib/ to use as a simulated drive.
• Permanent hard disks:
  • A GemDOS folder can represent multiple paritions by having its base directory contain only single-letter folder names representing drive letters. C/, D/, etc.
  • ACSI, SCSI and IDE hard disks use a binary image file chosen from system/hatarib/.
• Temporary hard disks:
  • You can also load one or more temporary hard disk images directly as content, or through an M3U playlist. The type of hard disk is selected by the filename extension.
  • ACSI images use an ACSI, AHD or VHD extension.
  • SCSI images use an SCSI or SHD extension.
  • IDE images use an IDE extension.
  • GemDOS folders use a dummy file with a GEM extension. Place this file next to a folder with the same name. The file can be empty, as its contents will not be used.
  • The GemDOS and IDE hard disk types can be adjusted futher in the core options.
  • An M3U image can load one or more temporary hard disk images. Simply add another line with the name of the hard disk image, after any floppy disks.
• Hard disks are read-only by default for safety. This can be disabled in the System > Hard Disk Write Protect core option. On some Libretro platforms, temporary hard drives may not be writable due to filesystem security settings.
• Because a hard disk image is not included with a savestate, file writes that are interrupted may cause corruption of the disk image's filesystem.
• Later TOS versions (or EmuTOS) are recommended when using hard drives, as TOS 1.0 has only limited support for them. Without EmuTOS you may need to use a hard disk driver.
• Using more than one permanent hard disk image at a time is unsupported, though a single image can have multiple partitions with individual drive letters. An M3U can be used for multiple temporary hard disks.
• If you need an easy way to switch between permanent hard disk configurations, you could create a "boot" floppy disk to go along with the hard disk, and use Manage Core Options > Save Game Options to create a settings override associated with that floppy.
• See Hatari's Manual: Hard Disk Support for further information.

M3U playlists and Auto-Run

• M3U playlists can be used to specify a collection of disk images, accessible via Disc Control in the Quick Menu of RetroArch.
• Each line of the M3U is the filename of a disk image, relative to the M3U file.
• A line starting with # will normally be ignored, allowing you to write a comment on the rest of that line, if needed.
• The first 2 disk images will be loaded into drives A and B when the content is opened, but this behaviour can be overridden.
  • A temporary hard disk image can also be listed in the M3U. Place hard disks after any floppy disk mages.
• #AUTO:filename can be used to automatically run a TOS file at boot. This is the same as Hatari's --auto command line option. TOS 1.04 or later is required to use this feature. Example: #AUTO:C:\GAMES\JOUST.PRG
• #BOOTA:number can be used to select an image from the list to insert into drive A at boot. 1 is the first image in the list. 0 will leave the drive empty.
• #BOOTB:number selects the image for drive B at boot.
• If using the #AUTO/#BOOTA/#BOOTB features, technically #EXTM3U should be added as the first line of the M3U to indicate this is an Extended M3U, but hatariB will not enforce this.
• Manage Core Options > Save Game Options can be used to associate other core options with an M3U playlist.
• Saving:
  • When a modified floppy disk is ejected, or the core is closed, a modified copy of that disk image will be written to the saves/ folder.
  • Whenever a new floppy disk is added (Load Content, or Load New Disk), the saved copy will be substituted for the original if it exists. (Also, if you want to return to the original disk, you can delete it from saves/.)
  • If the System > Save Floppy Disks core option is disabled, only the original copy of the file will be used, and the saves/ folder will not be accessed. However, the modified disk images will still persist in memory for the duration of the session, until you close the content.
  • Only the two currently inserted disks are included in savestates. If there are other disks in your loaded collection, they may take on their most recent version from the saves/ folder next time you open this content. A savestate will not be able to restore them to an earlier version.
  • Floppy disks in saves/ must have a unique filename. Try not to use generic names like savedisk.st, and instead include the game title in its filename. (Even if contained within a ZIP the save disk filename should be unique.)
  • If possible, it is recommended that save disks for games use the ST format, because it is the simplest and least error prone format. You can download a prepared blank disk here: blank.st.
  • The images written to saves/ will be standard Atari ST image formats, and you should be able to load them in other emulators if you wish.
  • Note that Hatari is not able to simulate the formatting of a blank disk in-emulator. The stand-alone version of Hatari has a utility in its menu that can be used to create a blank ST file. A different Atari ST emulator Steem.SSE can simulate the formatting process.
  • In the core options Advanced > Write Protect Floppy Disks will act as if all inserted disks have their write protect tab open. This means the emulated operating system will refuse to write any further data to the disk, and will report the error. This is independent of the save feature, and can be turned on and off at will. Turning it on after a disk is modified will not prevent previous modifications from being saved when it is ejected.
  • STX saves will create a WD1772 file instead of an STX when saved. This is an overlay of changes made to the file, because the STX format itself cannot be re-written. If you wish to use these with the stand-alone Hatari, place the overlay file in the same folder as its STX.
  • DIM format disks cannot be saved by Hatari. It is recommended to convert them to ST files instead.
  • IPF and CTR format disks cannot be saved by Hatari.
  • Hard Disk folders or images in system/ will be written to directly when they are modified.
  • The TT and Falcon machines have a small non-volatile RAM (NVRAM) that stores system settings. This is saved to system/hatarib.nvram when the content is closed.
• TOS ROMs:
  • The TOS ROM can be chosen in the core option Sstem > TOS ROM.
  • The default TOS ROM is system/tos.img, but EmuTOS is provided built-in as a free substitute.
  • Additional TOS ROMs can be supplied in system/hatarib/, up to a limit of 100 files.
  • EmuTOS is compatible with most software, but not all. In most incompatibility cases it will show a "Panic" message at boot.
  • EmuTOS 1024k has a full feature set, and univeral support for all emulated machine types.
  • EmuTOS 192uk may be slightly more compatible with ST software, but provides fewer features. With a colour monitor it starts up in 50hz. This was chosen as a default for the greatest compatibility with games.
  • EmuTOS 192us is similar to 192uk but instead starts in 60hz.
  • Most other TOS files are only compatible with certain machines.

On-Screen Keyboard

• An on-screen keyboard can be used to simulate using the Atari's keyboard from your gamepad.
• Press L1 to raise the on-screen keyboard, select a key with the d-pad, and press L1 again to press the key. Press R1 to close the keyboard.
• Press R1 to raise the keyboard in one-shot mode, which pauses emulation and will resume immediately when you press L1 to press the key, or R1 to cancel.
• To alternate between a top and bottom keyboard position, press X.
• Modifier keys like Shift, Control, Alt are toggled instead of a single press, allowing you to hold the modifier while you press another key. When you close the keyboard, all modifiers will be released.
• The keyboard language layout can be chosen in the Input > On-Screen Keyboard Language core option. This should usually be chosen to match your TOS region.
• MIDI:
  • Libretro has a MIDI interface, and if you have MIDI devices installed you should be able to select them in the Settings > Audio > MIDI menu of RetroArch.
  • The MUNT MT-32 Emulator is recommended. It can install on your system as a MIDI device, which you can use with MT-32 supporting Atari ST games.
• Accuracy:
  • Some of the default core options are chosen to favour faster load times, but these can be adjusted:
    • System > Fast Floppy gives artificially faster disk access, on by default.
    • System > Patch TOS for Fast Boot modifies known TOS images to boot faster, on by default.
  • Other accuracy options might be adjusted for lower CPU usage:
    • System > CPU Prefetch Emulation - Emulates memory prefetch, needed for some games. On by default.
    • System > Cycle-exact Cache Emulation - More accurate cache emulation, needed for some games. On by default.
  • See the Advanced category for other relevant options.

Savestates

• Savestates are seamless, allowing run-ahead and netplay.
• Load New Disk has several caveats with savesates:
  • RetroArch will change the savestate name to match the newest loaded disk, so be sure that you know what savestates are associated with that disk.
  • To restore in a later session, start the core as you did before and use Load New Disk to add all needed disks before attempting to restore the savestate. The last disk loaded must be the same as before, so that the savestate name will match correctly.
  • In rare cases, inserting a unusually large new disk may increase the needed savestate size and cause a failure to save. You can eject the disk and try reducing the savestate size before trying again. (RetroArch has a limitation that savestate size must be fixed, determined at Load Content time.)
  • It is generally recommended to use M3U playlists instead of Load New Disk when possible (tutorial).
• Hard Disk modifications are written directly to their source files, and are not included in savestates. Try to avoid making savestates during a hard disk write.
• If you increase the size of the Atari system memory, you should close content and restart the core before using savestates, to allow RetroArch to update the savestate size.
• For run-ahead or netplay disable System > Floppy Savestate Safety Save to prevent high disk activity. When enabled, this option causes any savestate reload to always rewrite a disk to your saves folder if a save file for it already exists here. This helps prevent losing unsaved data when reloading longer term save states, but makes the rapid savestates needed for run-ahead significantly slower.
  • Enabling Advanced > Write Protect Floppy Disks will also prevent the safety save feature, as it will not allow the disk to be modified at all.

Netplay

• Disable System > Floppy Savestate Safety Save, or consider enabling Advanced > Write Protect Floppy Disks. See note about savestates above.
• Disable Input > Host Mouse Enabled and Input > Host Keyboard Enabled, because RetroArch netplay does not send this activity over the network. Instead, use the onscreen keyboard and gamepad to operate the ST keyboard and mouse.
• RetroArch does not allow analog stick inputs during netplay. The RetroPad > Joystick / Mouse Toggle button assignment may be useful for switching between mouse and joystick d-pad input during netplay.
• Make sure your core options match, especially the TOS image, before attempting to connect.
• Netplay for hatariB may be more network and CPU intensive than other retro sytems, due to the large onboard RAM of the ST, and volatile floppy disk media.
• The Libretro API does not provide a way to detect whether netplay is active, so appropriate setting changes like the safety save unfortunately can't be done automatically.
• The IPF format appears to have drive state that cannot be completely restored, a limitation of the capsimg library. Netplay may have problems after disk activity when using IPF disk images, due to savestate divergence.

Unsupported Features

• Printer
• RS232
• Host keyboard remapping
• Falcon microphone

Quirks

• If the on-screen keyboard confirm/cancel buttons aren't mapped to dedicated buttons, you might end up suddenly holding the underlying button when the keyboard closes. (Inputs from buttons mapped to the on-screen keyboard are suppressed while it remains open.)
• Though the on-screen keyboard is available in several language layouts, for your physical keyboard there aren't any direct configuration options, currently. RetroArch ignores the OS keyboard layout, and all keys report as-if in US layout (e.g. German Z reports as RETROK_y). Because of this, if you pick a TOS that matches your keyboard language, the mappings are likely to be mostly compatible. Otherwise, if you need finer control of the mapping, RetroArch's Input settings can be used to remap individual keys.
• The Floppy Disk List pause screen can only display a limited subset of unicode characters, due to Hatari's UI font. They can still be viewed through RetroArch's Disk Control menu when the selected drive is ejected.
• There is no way to designate individual floppy disks as read-only. In Hatari this was detected by the host filesystem's read-only attribute on the file, but in Libretro this information is not available. The Advanced > Write Protect Floppy Disks provides a coarse way to override this. However, note that any modifications to the file are saved to a copy in the user's saves/ folder, so the original floppy image is never modified, regardless of setting.
• You can use Load New Disk or M3U playlists to load the same floppy multiple times, or multiple floppies with the same name. This mostly works okay, but a savestate restore might be unable to identify which of them was actually inserted.
• If IPF support is enabled, an M3U playlist can also be used to load the RAW format supported by that library. I kept it out of the associated file types list because I have not yet encountered dumps in this format.
• The Advanced > CPU Clock Rate core option is only applied at boot/reset, but you can CPU Speed to a gamepad button in the RetroPad core options to change it while running.
• Because this core has keyboard control support, when a game is started in a window RetroArch seems to have a bug that restricts the mouse to the current monitor. You can click off the window or Alt+Tab to get away. (The bug may have something to do with failing to "ungrab" the mouse in response to game focus being turned off at game launch? Not sure.)

History

• hatariB v0.4 - Unreleased
  • EmuTOS 192uk chosen as default for best compatibility.
  • EmuTOS 1.3 ROMs.
  • Fixed problems with IPF emulation.
  • Hatari 2.5.0 update.
  • SDL2 2.30.2 update.
  • Raspberry Pi builds now have dlopen available for capsimg support.
  • Multi-file ZIP/ZST support, also with M3U playlist inside.
  • Fixed incorrect "Failed to set last used disc..." RetroArch notification.
• hatariB v0.3 - 2024-04-15
  • On-screen keyboard improvements:
    • Can now hold the key continuously.
    • Auto-repeat for a held direction.
    • Pressing up from space bar now remembers last key instead of always going to Z.
  • Fixed blitter hang when using cycle-accurate cache emulation.
  • Single button disk swap.
  • Savestate optimizations, making run-ahead and netplay viable.
  • Savestate determinism improvements to reduce netplay re-synchronizations.
  • Fix CPU clock rate change on reset.
  • CPU speed button mapping.
  • Joystick / Mouse Toggle button mapping.
  • 4:3 pixel aspect ratio option.
  • Medium resolution vertical-doubling can be disabled.
  • Resolution doubling settings now work for TT and Falcon.
  • Border cropping settings now apply to Falcon.
  • Hard disk images can be loaded as content.
  • M3U can be used to auto-run a program at boot.
  • Fixes to savestates on non-Windows platforms.
  • Attempting to make savestates as cross-platform compatible as possible.
  • Option to disable boot notification.
  • Fixed out-of-date screen image during pause/one-shot and savestate/netplay/run-ahead.
  • Android builds.
  • Multiple hard disk support.
  • MacOS Fat build (Intel 64-bit, Apple Arm).
  • M3U can be used to select disk image or empty drive at boot.
• hatariB v0.2 - 2023-09-07
  • Second beta test version.
  • IPF support via dynamic loading of capsimg library.
  • Raspberry Pi builds.
  • Onscreen keyboard layouts for all known ST languages.
  • Notification messages for hard disk load errors.
  • Correct aspect ratios.
  • Border cropping options.
  • Performance profiling option.
• hatariB v0.1 - 2023-08-22
  • First beta test version.

License

This project is licensed under the GNU General Public License Version 2.

The GPL v2 license was inherited from the Hatari project. The Hatari source code is incorporated here, in the hatari/ folder with minimal modifications, outlined in the development notes.

This project includes EmuTOS binaries as built-in available TOS BIOS images, under the GPL v2 license.

This project incorporates header files from Libretro, under a compatible permissive license.

This project includes SDL2 under the zlib license.

This project includes zlib under the zlib license.

Authors

This Libretro core was begun by Brad Smith.

Other contributors:

• DJM75 - Android build.

Incorporated works contributor documentation:

• Hatari
• EmuTOS
• libretro.h
• libretro_sdl_keymap.h
• SDL2
• zlib

I would also like to acknowledge the prior work of libretro/hatari project:

• libretro/hatari

Though none of hatariB's code is directly borrowed from libretro/hatari (aside from our mutual use of Hatari), as a past contributor I had learned much from it. As an example to work from and compare against, it was a direct inspiration and source of ideas for hatariB.