emulator: DeSmuME
type: libretro
source: "https://github.com/libretro/desmume"
profiled_date: "2026-03-18"
core_version: "SVN"
display_name: "Nintendo - DS (DeSmuME)"
cores: [desmume, desmume2015]
systems: [nintendo-ds]

notes: |
  DeSmuME provides full HLE (High-Level Emulation) of all ARM7/ARM9 SWI
  routines, making BIOS files optional for most games. When external BIOS
  is disabled, a minimal fake BIOS with exception vectors and IRQ handler
  stubs is generated at runtime (NDSSystem.cpp:2208-2224, 2263-2278).
  External BIOS enables SWI-from-BIOS mode and firmware boot animation.
  Firmware boot requires both ARM7+ARM9 BIOS loaded AND interpreter mode
  (JIT incompatible, see libretro.cpp:788).
  ARM9 BIOS read size: 4096 bytes (0x1000). ARM7 BIOS read size: 16384
  bytes (0x4000). No DSi support.
  Libretro core option: desmume_use_external_bios (enabled/disabled).

files:
  - name: "bios7.bin"
    system: nintendo-ds
    description: "ARM7 BIOS"
    required: false
    size: 16384
    source_ref: "desmume/src/NDSSystem.cpp:2178-2182, frontend/libretro/libretro.cpp:763"
    notes: "HLE fallback covers all SWI calls; native file needed for firmware boot and SWI-from-BIOS accuracy"

  - name: "bios9.bin"
    system: nintendo-ds
    description: "ARM9 BIOS"
    required: false
    size: 4096
    source_ref: "desmume/src/NDSSystem.cpp:2236-2239, frontend/libretro/libretro.cpp:764"
    notes: "HLE fallback covers all SWI calls; native file needed for firmware boot and logo comparison (Pal Park)"

  - name: "firmware.bin"
    system: nintendo-ds
    description: "NDS firmware image"
    required: false
    source_ref: "desmume/src/NDSSystem.cpp:2653-2655, frontend/libretro/libretro.cpp:765"
    notes: "Dummy firmware generated when absent; native firmware needed for boot animation, wifi config, user settings"