emulator: ARMSX1
type: standalone
core_classification: community_fork
source: "https://github.com/ARMSX2/ARMSX1"
source_branch: "android-compose"
upstream: "https://github.com/allkern/psxe"
profiled_date: "2026-08-11"
source_commit: "fadd20b6587a291e59b49378a2428358c6663b8c"
core_version: "0.1.3"
display_name: "Sony - PlayStation (ARMSX1)"
verification: existence
bios_size: 524288
bios_directory: "bios/"
cores:
  - armsx1
systems:
  - sony-playstation

notes: |
  PlayStation emulator forked from psxe, rebuilt around SDL2 frontends and a
  Dear ImGui fullscreen shell. Desktop, Android, iOS, UWP, WebAssembly and
  PSVita builds come out of one tree. The Android application is
  com.nanodata.armsx with the activity com.armsx2.Main, and its Compose
  launcher hosts the same core in process.
  ref: README.md:1-2, android/app/build.gradle:71-79,
       android/app/src/main/AndroidManifest.xml:78-92

  A BIOS image is required. Boot stops before a session exists when no path
  resolves, and again when the file cannot be read. Skip BIOS does not change
  that: the image runs from reset and the hook only takes over at the shell
  entry point, once the kernel is built.
  ref: frontend/main.cpp:2529-2549, psx/psx.c:249-252, psx/fastboot.h:45,
       psx/fastboot.c:225-239

  psxe_cfg_get_bios_path answers in three steps: the override file when it
  exists, then a scan of the search folder, then the override path unchanged.
  The override is [bios].override_file or -b and defaults to bios.bin under the
  preference path SDL_GetPrefPath("nanodata", "armsx"); the search folder is
  [bios].search_path or -B and defaults to the relative path bios.
  ref: frontend/config.c:1540-1559, frontend/config.c:1385-1404,
       frontend/config.c:677-683, frontend/config.c:54-57

  The scan reads that folder once, keeps .bin and .rom, and returns the entry
  named bios.bin. Its other branch compares [bios].preferred_model against each
  filename through a normaliser that drops every non-alphanumeric character and
  lowercases the rest, applied to the name including its extension, so
  scph1001.bin normalises to scph1001bin and no model value equals it. A name
  carrying no extension, which would, is dropped by the extension filter first.
  ref: frontend/config.c:292-357, frontend/config.c:226-247,
       frontend/config.c:249-260

  Nothing identifies the image beyond that. No name table, no size test, no
  hash. The loader takes the file's own length, allocates it, and the bus maps
  the device from 0x1fc00000 over that same length, which is how the 1 MB
  SCPH-5903 image stays addressable in full.
  ref: psx/dev/bios.c:21-54, psx/bus.c:50-54, psx/dev/bios.h:8-10

  preferred_model carries 22 values, SCPH-1000 through SCPH-102C, printed by
  --help-model and mirrored by the Android model picker.
  ref: frontend/config.c:177-200,
       android/app/src/main/java/com/armsx2/config/Ps1Settings.kt:416-423

  On Android the preference path is the application files directory, so
  settings.toml and the default bios.bin sit there. The BIOS picker copies the
  chosen dump to user_bios.bin and writes its absolute path into
  [bios].override_file. EmulatorActivity passes --bios <files>/bios.bin when
  the package carries an assets/bios.bin, and the in-process launcher repeats
  that check with stat; release 0.1.3 ships no such asset.
  ref: android/app/src/main/java/com/armsx2/core/Ps1Config.kt:20-41,
       android/app/src/main/java/com/armsx2/ui/settings/Ps1BiosTab.kt:38-48,
       android/app/src/main/java/com/nanodata/armsx/EmulatorActivity.java:58-61,
       android/app/src/main/java/com/nanodata/armsx/EmulatorActivity.java:95-99,
       frontend/android_jni.cpp:1708-1743, ARMSX1-0.1.3-release.apk assets

  The remaining paths the core opens are per game, and are written by the
  emulator or picked by the user: memory cards, created blank at first use;
  save states, rewind snapshots and screenshots; a GameShark .cht catalogue
  named by [cheats].cheats_file; and content-addressed PNG packs under the
  replacements folder of [video].texture_dir.
  ref: psx/dev/mcd.c:139-154, psx/cheats.c:346-390, psx/texrep.c:846-848

files:
  - name: scph1001.bin
    agnostic: true
    required: true
    min_size: 524288
    max_size: 1048576
    description: "PlayStation BIOS image"
    note: >-
      Any image is accepted, whatever its name and length: the file is read
      whole and mapped at its own size. 524288 is the region psx_bios_init
      declares before the load, and 1048576 the SCPH-5903 image the loader
      names as the exception. The folder scan reaches an image only under the
      name bios.bin; [bios].override_file, -b and the Android picker open a
      path directly.
    source_ref: "psx/dev/bios.c:21-54, psx/dev/bios.h:8-10, frontend/config.c:292-357, frontend/config.c:1540-1559, frontend/main.cpp:2529-2535"

  - name: "<expansion>.rom"
    required: false
    config_key: "paths.expansion_rom"
    max_size: 524288
    unsourceable: "any expansion port ROM the user points at, under no name and no version the code expects"
    description: "Expansion port ROM image"
    note: >-
      Read into the 512 KB region at 0x1f000000, which is filled with 0xff when
      no path is set. Named by [paths].expansion_rom, -e, or the Advanced tab of
      the Android settings. A path that is set and cannot be opened fails
      psx_init and stops the boot.
    source_ref: "psx/dev/exp1.c:12-44, psx/dev/exp1.h:8-10, psx/psx.c:260-261, frontend/config.c:681, frontend/main.cpp:1906, android/app/src/main/java/com/armsx2/ui/settings/Ps1AdvancedTab.kt:96-100"