v2026.04.02/emulators/mu.yml

emulator: Mu
type: libretro
core_classification: pure_libretro
source: "https://github.com/libretro/Mu"
upstream: "https://github.com/meepingsnesroms/Mu"
profiled_date: "2026-03-24"
core_version: "v1.3.3"
display_name: "Palm OS (Mu)"
cores: [mu]
systems: [palm-os]

notes: |
  Mu emulates Palm m500, Palm m515, and (with EMU_SUPPORT_PALM_OS5)
  Tungsten T3. A Palm OS ROM dump is required. The core selects the
  ROM filename based on the "OS Version" core option:
    Palm m500 / Palm OS 4.0   -> palmos40-en-m500.rom
    Palm m515 / Palm OS 4.1   -> palmos41-en-m515.rom  (default)
    Tungsten T3 / Palm OS 5.2 -> palmos52-en-t3.rom
    Tungsten T3 / Palm OS 6.0 -> palmos60-en-t3.rom

  ROM path: RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY + "/" + osVersion + ".rom".
  No hash or size validation; the code reads whatever file is present.
  The bootloader is optional and ignored for Tungsten T3.
  Supports no-game mode (boots Palm OS desktop from ROM without content).

files:
  # --- Palm m515 / Palm OS 4.1 (default device) ---
  - name: "palmos41-en-m515.rom"
    system: palm-os
    description: "Palm m515 ROM, Palm OS 4.1 English"
    required: true
    note: "Default ROM. Selected when core option is 'Palm m515/Palm OS 4.1'."
    source_ref: "libretroBuildSystem/libretro.c:173-176 (check_variables), 744-763 (retro_load_game ROM loading)"

  # --- Palm m500 / Palm OS 4.0 ---
  - name: "palmos40-en-m500.rom"
    system: palm-os
    description: "Palm m500 ROM, Palm OS 4.0 English"
    required: false
    note: "Selected when core option is 'Palm m500/Palm OS 4.0'."
    source_ref: "libretroBuildSystem/libretro.c:169-172"

  # --- Tungsten T3 / Palm OS 5.2.1 (requires EMU_SUPPORT_PALM_OS5) ---
  - name: "palmos52-en-t3.rom"
    system: palm-os
    description: "Tungsten T3 ROM, Palm OS 5.2.1 English"
    required: false
    note: "Selected when core option is 'Tungsten T3/Palm OS 5.2.1'. Requires EMU_SUPPORT_PALM_OS5 compile flag."
    source_ref: "libretroBuildSystem/libretro.c:178-181"

  # --- Tungsten T3 / Palm OS 6.0 (requires EMU_SUPPORT_PALM_OS5) ---
  - name: "palmos60-en-t3.rom"
    system: palm-os
    description: "Tungsten T3 ROM, Palm OS 6.0 English"
    required: false
    note: "Selected when core option is 'Tungsten T3/Palm OS 6.0'. Requires EMU_SUPPORT_PALM_OS5 compile flag."
    source_ref: "libretroBuildSystem/libretro.c:182-185"

  # --- MC68VZ328 bootloader ---
  - name: "bootloader-dbvz.rom"
    system: palm-os
    description: "MC68VZ328 UART bootloader"
    required: false
    note: "Optional for m500/m515. Ignored for Tungsten T3."
    source_ref: "libretroBuildSystem/libretro.c:766-782, src/dbvz.c:1408-1423 (dbvzLoadBootloader)"

platform_details:
  palm_m5xx:
    rom_size: 4194304       # 4 MB (M5XX_ROM_SIZE)
    bootloader_size: 512    # DBVZ_BOOTLOADER_SIZE (0x200)
    cpu: "MC68VZ328"
    source_ref: "include/m5XXBus.h:23,28, src/emulator.c:191-212"

  tungsten_t3:
    rom_size: 16777216      # 16 MB (TUNGSTEN_T3_ROM_SIZE)
    cpu: "PXA260 (ARM)"
    source_ref: "include/tungstenT3Bus.h:17, src/emulator.c:145-162"