emulator: "Swan.emu" type: standalone core_classification: community_fork source: "https://github.com/Rakashazi/emu-ex-plus-alpha" upstream: "https://mednafen.github.io/" profiled_date: "2026-08-12" source_commit: "1c12fac5ce49badaadff2e2f210dcc30b89f4943" core_version: "1.5.85" display_name: "Bandai - WonderSwan / Color (Swan.emu)" mode: standalone cores: - "swan-emu" - "Swan.emu" - "SWAN-EMU" systems: - bandai-wswan - bandai-wswanc notes: | Member of the EX Emulator series by Robert Broglia, which targets Android and Linux (README.md:1,3-4,12-13) and keeps iOS and Pandora build shortcuts in the tree (Swan.emu/ios.mk, Swan.emu/pandora.mk). Published as com.explusalpha.SwanEmu (Swan.emu/metadata/conf.mk:2,6,7) and reached by ES-DE through its SWAN-EMU find rule, which only the Android rule set carries. Mednafen's WonderSwan module, itself descended from Cygne, is vendored under Swan.emu/src/wswan (Swan.emu/metadata/conf.mk:8, Swan.emu/src/main/AppMeta.cc:27) on the 1.32 line (EmuFramework/include/shared/mednafen/mednafen-config.h:167) and driven by the app's own video, audio, input and save layers. Three files differ from the Mednafen 1.32.1 release: the pixel format and sound rate hooks move to the app and the button latch is dropped for a value the input layer writes directly, the save file calls are removed from loading and closing, and the SRAM and EEPROM writes signal the app's backup memory (Swan.emu/src/wswan/main.cpp:91,95, Swan.emu/src/main/Main.cc:96,104,119, Swan.emu/src/main/input.cc:97,102, Swan.emu/src/wswan/memory.cpp:160-164, Swan.emu/src/wswan/eeprom.cpp:164-169). The debugger and the disassembler are left out of the build (Swan.emu/src/CMakeLists.txt:6-22). Content is read from .ws, .wsc and .bin files (Swan.emu/metadata/conf.mk:5, Swan.emu/src/main/AppMeta.cc:30). An archive is opened by the framework, which keeps the first entry passing that same filter (EmuFramework/src/EmuSystem.cc:394-412). The content image is the only one the app loads. It is read into a 64 MiB buffer, refused under 64 KiB or over 64 MiB, rounded up to 64 KiB then to a power of two with the image sitting at the end of the buffer, and hashed for the save file names (Swan.emu/src/main/Main.cc:91-97, EmuFramework/src/shared/mednafen-emuex/MDFNUtils.hh:133-146, Swan.emu/src/wswan/main.cpp:236-257,294-299). Byte 5 of the footer selects either an EEPROM of 128, 1024 or 2048 bytes or battery RAM of 8 KiB to 512 KiB (Swan.emu/src/wswan/main.cpp:317-333). A 512 KiB image carrying ELISA at 0x70000 whose last 16 bytes hash to crc32 0x0d05ed64, minus three blacklisted images, is taken for WonderWitch firmware and read as content (Swan.emu/src/wswan/main.cpp:273-291,351-352). No boot ROM is read. Reset writes a built-in table of 200 power-on values to the I/O ports, less the four EEPROM data ports (Swan.emu/src/wswan/start.inc:12, Swan.emu/src/wswan/main.cpp:66-70) and the memory reset writes at 0x75AC the eight identifier bytes the boot ROM would have left (Swan.emu/src/wswan/memory.cpp:801-808). The internal EEPROM is a built-in 0x400 byte image copied at init, then personalized in place with the name, birth date, sex and blood type of the WonderSwan User Profile menu, and the language flag reaches the hardware the same way (Swan.emu/src/wswan/eeprom.cpp:31,33,183-214, Swan.emu/src/wswan/memory.cpp:748-772, Swan.emu/src/wswan/main.cpp:377, Swan.emu/src/main/EmuMenuViews.cc:34-155, Swan.emu/src/main/options.cc:117-165). No firmware path exists by construction: the app answers Mednafen's file name request for save states, saves and save backups only, and any other kind ends in unreachable() (Swan.emu/src/main/options.cc:179-189). The module's own save reader and writer, which would open a .sav and, for WonderWitch, a 524288 byte .flash image, are unreachable, both call sites of the Mednafen release having been removed from loading and closing (Swan.emu/src/wswan/memory.cpp:674-740, Swan.emu/src/wswan/main.cpp:223-226,377-379). The comms setting is answered false and its program path empty, so the serial link never forks a helper (Swan.emu/src/main/options.cc:159-160,173-174, Swan.emu/src/wswan/main.cpp:379, Swan.emu/src/wswan/comm.cpp:40-71). Cheat loading and IPS patching are compiled in from the shared Mednafen sources and called from nowhere (EmuFramework/src/shared/CMakeLists.txt:11-12, EmuFramework/src/shared/mednafen/mempatcher.cpp:251-254, EmuFramework/src/shared/mednafen/file.cpp:38-53), and the music rip player routines are stubs (EmuFramework/src/shared/mednafen-emuex/MDFNApi.cc:87-88, Swan.emu/src/wswan/main.cpp:259-268). Per content the app writes and reads back one .sav holding the EEPROM followed by the battery RAM, plus save states and SwanEmu.config (Swan.emu/src/main/Main.cc:47-54,56-82, Swan.emu/src/main/system.ccm:155, Swan.emu/src/main/AppMeta.cc:28, EmuFramework/src/shared/mednafen-emuex/MDFNUtils.hh:76-122, EmuFramework/src/EmuSystem.cc:168-172). ui.png, gpOverlay.png and the shader sources are drawn from the application bundle (EmuFramework/include/emuframework/AssetManager.hh:61-66, EmuFramework/src/AssetManager.cc:58-70, EmuFramework/src/VideoImageEffect.cc:163-173), as is the interface font on a build without fontconfig (imagine/src/font/FreetypeFont.cc:271-289). The app declares no bundled content, the framework definition defaulting to an empty span (EmuFramework/src/AppMeta.cc:40, EmuFramework/include/emuframework/AppMeta.hh:66-68). files: []