emulator: "Mini vMac 37"
type: standalone
core_classification: community_fork
source: "https://github.com/minivmac/minivmac"
profiled_date: "2026-10-20"
source_commit: "6860a9a7f372c461b25dc42974b191a453ebcfb2"
core_version: "37.03"
display_name: "Apple - Macintosh Plus (Mini vMac 37)"
mode: standalone
cores: []
systems:
  - apple-macintosh

notes: |
  Mini vMac 37.03 (setup/SPBASDEF.i:21-24), maintained from Paul C. Pratt's
  code (setup/SPBASDEF.i:30). The emulated model, the ROM name, the ROM size
  and the accepted checksums are fixed when the setup tool writes the build configuration, so one binary runs
  one model. The default model is the Macintosh Plus (setup/SPBLDOPT.i:101,108).
  The entries below describe a build with -m Plus, which is also the default.

  The setup tool names the ROM after the model (setup/SPCNFGAP.i:28-63):
  Twig43.ROM (Twig43), Twiggy.ROM (Twiggy), Mac128K.ROM (128K),
  MacPlusKanji.ROM (Kanji), MacSE.ROM (SE), SEFDHD.ROM (SEFDHD), Classic.ROM
  (Classic), PB100.ROM (PB100), MacII.ROM (II), MacIIx.ROM (IIx) and vMac.ROM
  for 512Ke and Plus. ROM sizes per model are set at setup/SPBLDOPT.i:3229-3257
  and the per-model checksums at setup/SPCNFGAP.i:81-126. A build for another
  model reads only the name of that model.

  The SDL backend (-api sdl, sd2 or sd3, src/OSGLUSDL.c) looks for the ROM in
  this order (src/OSGLUSDL.c:606-620): the path given by --rom or -r
  (src/OSGLUSDL.c:4962-4968), the directory given by -d or else the directory
  of the executable from SDL_GetBasePath (src/OSGLUSDL.c:576-604,5185), the
  mnvm_rom folder under SDL_GetPrefPath("gryphel", "minivmac")
  (src/OSGLUSDL.c:546-573,5187), then the working directory. The executable
  directory and the preference folder are searched only on SDL 2 and later
  (src/OSGLUSDL.c:67-72). The default Linux backend is X11
  (setup/GNBLDOPT.i:1609-1621), which searches the command line path, the
  executable directory, ~/.gryphel/mnvm_rom/ and the working directory
  (src/OSGLUXWN.c:957-1022).

  When no ROM loads, the emulator keeps running and waits for a ROM image
  dropped on its window (src/OSGLUSDL.c:470-483,620).

  At startup the SDL backend mounts disk1.dsk to disk9.dsk from the executable
  directory, stopping at the first missing one (src/OSGLUSDL.c:486-540). These
  are user disk images.

files:
  - name: "vMac.ROM"
    system: apple-macintosh
    path: "vMac.ROM"
    required: true
    min_size: 131072
    validation: [size]
    source_ref: "setup/SPCNFGAP.i:60-63,115-124, setup/SPBLDOPT.i:3240-3243, src/OSGLUSDL.c:435-468,606-620, src/CONTROLM.h:1314-1326,1344-1388"
    note: >
      Macintosh Plus ROM. LoadMacRomFrom reads kROM_Size bytes, 131072 for the
      Plus (setup/SPCNFGGL.i:73-77), and rejects a shorter file. ROM_IsValid
      then compares the first long word of the image with the three Plus
      checksums 0x4D1EEEE1 (v1), 0x4D1EEAE1 (v2) and 0x4D1F8172 (v3), and
      recomputes the sum of the 16-bit words from offset 4 over 131072 bytes,
      which must equal the stored value. A ROM that fails either test is
      refused. The -chr 0 setup option compiles both tests out
      (setup/SPBLDOPT.i:3288-3311, setup/SPCNFGAP.i:128-130,
      src/CONTROLM.h:1309-1310).