emulator: EmuSCV
type: libretro
core_classification: community_fork
source: "https://git.libretro.com/libretro/libretro-emuscv"
upstream: "http://takeda-toshiya.my.coocan.jp/"
profiled_date: "2026-11-09"
source_commit: "33900ce24f45c429b533fdae7844e04d64a9a1b9"
core_version: "0.15.20260921084155"
version_basis:
  kind: file
  path: "src/emuscv.h"
  pattern: 'EMUSCV_VERSION_MAJOR\s+"(\d+)"\n#define EMUSCV_VERSION_MINOR\s+"(\d+)"\n#define EMUSCV_VERSION_DATETIME\s+"(\d+)"'
  format: "{1}.{2}.{3}"
display_name: "EPOCH/YENO Super Cassette Vision (EmuSCV)"
cores:
  - emuscv
systems:
  - scv

notes: |
  Libretro port of eSCV by Takeda Toshiya (Common Source Code Project),
  ported to libretro by MARCONATO Maxime. Upstream source mirrored at
  https://github.com/tautologico/common-src-project (src/vm/scv/). The
  buildbot builds libretro's copy on git.libretro.com, which carries the
  history of the former GitHub repository and continues it.

  BIOS loading in src/vm/scv/memory.cpp:initialize() (lines 84-250).
  Tries filenames in order: upd7801g.s01, upd7801g.bin, upd7801g.bios,
  bios.rom, bios.bin. First successful open wins. Upstream eSCV uses
  only BIOS.ROM (uppercase), and the libretro port renamed and added
  fallback aliases.

  The BIOS is read as 0x1000 (4096) bytes into the bios[] array, mapped
  read-only at CPU address 0x0000-0x0FFF (UPD7801 internal ROM area).

  upd7801g.s01 is checked against MD5 635a978fd40db9a18ee44eff449fc126
  unless the CHECKBIOS core option is NO, so with the default AUTO a
  file of other content under that name is rejected (filled with 0xFF,
  bios_loaded=false) and the next name is tried. The four other names are
  checked only when CHECKBIOS is YES, and AUTO accepts any content under
  them (src/vm/scv/memory.cpp:84-112, 115-148, src/emuscv.cpp:3459-3472).

  The font/character data is embedded within the BIOS at offset 0x200
  (memory.h get_font() returns bios + 0x200). No separate font ROM file.

  The core can start without BIOS (supports_no_game=true) but shows
  "BIOS not found" or "Bad BIOS" on the OSD. Games will not run without
  it.

  The .info declares firmware_count=1, firmware0_opt=false. Matches code.

files:
  - name: "upd7801g.s01"
    system: scv
    required: true
    size: 4096
    md5: 635a978fd40db9a18ee44eff449fc126
    validation: [md5]
    note: "UPD7801G internal ROM (BIOS). The MD5 is checked by default under this name only. Mapped at 0x0000-0x0FFF. Contains character font at offset 0x200."
    source_ref: "src/vm/scv/memory.cpp:84-250"
    aliases:
      - "upd7801g.bin"
      - "upd7801g.bios"
      - "bios.rom"
      - "bios.bin"

platform_details:
  cpu: "NEC UPD7801G"
  bios_mapping:
    upd7801g:
      target: "0x0000-0x0FFF (CPU internal ROM, 4 KB)"
      format: "raw binary"
      source_ref: "src/vm/scv/memory.cpp:259-264"
      notes: |
        Memory map from memory.cpp:initialize():
          0x0000-0x0FFF  BIOS ROM (read-only)
          0x2000-0x3FFF  VRAM (8 KB)
          0x8000-0xFF7F  Cartridge ROM (up to 4 banks of 32 KB)
          0xFF80-0xFFFF  CPU internal RAM (128 bytes)
        Font data lives inside the BIOS at offset 0x200, accessed via
        get_font() for the VDP character rendering (src/vm/scv/vdp.cpp).

  cartridge_loading:
    formats: "cart, bin, rom, 0 (multi-file: .0/.1/.2/.3), zip"
    banking: "4 banks of 32 KB via PC5/PC6 port lines"
    source_ref: "src/vm/scv/memory.h, src/vm/scv/memory.cpp"