emulator: VeMUlator
type: libretro
core_classification: official_port
source: "https://github.com/libretro/vemulator-libretro"
upstream: "closed-source Android app (removed from Google Play ~2020)"
profiled_date: "2026-03-25"
core_version: "0.1"
display_name: "VeMUlator"
cores:
  - vemulator
systems:
  - sega-vmu

notes: |
  Sega Dreamcast VMU/VMS emulator. Same author (Mahmoud Jaoune) ported
  the original Android Java app to C++ for libretro. Emulates the Sanyo
  LC8670 CPU, 128 KB flash, 48x32 LCD, piezo buzzer, and timers.

  No BIOS files required. The core uses HLE exclusively: startCPU()
  checks BIOSExists (always false), then initializeHLE() sets SFR
  registers and system RAM directly (vmu.cpp:193-222).

  A loadBIOS() function exists (vmu.cpp:82-137) handling encrypted and
  unencrypted BIOS images, but is never called from the libretro
  interface. retro_load_game() only loads game flash data, with no
  system directory query. README lists BIOS support as planned.

files: []

platform_details:
  hle_implementation:
    source_ref: "vmu.cpp:195-222"
    sfr_init:
      SP: "0x7F"
      PSW: "0x02"
      IE: "0x80"
      MCR: "0x08"
      P7: "0x02"
      OCR: "0xA3"
      BTCR: "0x41"
    ram_init:
      - "0x31 = 0xFF (battery level)"
      - "0x6E = 0xFF"
      - "P3 = 0xFF (no buttons pressed)"
      - "BCD date/time at 0x10-0x16, raw at 0x17-0x1D"
    notes: |
      HLE skips the BIOS boot sequence and jumps directly into the loaded
      game. System clock, date, and button state are initialized in RAM.
      The EXT register is set to 1 to signal HLE mode to the CPU
      (vmu.cpp:198-199). Games that depend on BIOS-initialized state
      beyond what HLE provides may not work correctly.

  unused_bios_loader:
    source_ref: "vmu.cpp:82-137"
    max_file_size: 61444
    rom_load_size: 61440
    encryption: "XOR 0x37 after stripping 4-byte header"
    detection: "first byte 0x2A (JMPF) = unencrypted, otherwise encrypted"
    notes: |
      The loadBIOS() method is fully implemented but unreachable from the
      libretro interface. No system directory query, no BIOS path construction,
      and no call site exists in main.cpp. A future update could wire this up
      to support real VMU firmware boot (file manager, clock, mini-games menu).