libretro/emulators/cspect.yml

emulator: CSpect
type: standalone
core_classification: other
source: "https://mdf200.itch.io/cspect"
upstream: "https://mdf200.itch.io/cspect"
profiled_date: "2026-08-11"
core_version: "3.3.1.0"
display_name: "Sinclair - ZX Spectrum Next (#CSpect)"
verification: existence
cores: [cspect]

systems:
  - sinclair-zx-spectrum-next
  - sinclair-zx-spectrum

notes: |
  ZX Spectrum Next emulator, assembler and debugger for Windows, macOS and
  Linux, written in C# against .NET Framework 4.8 and run under Mono elsewhere.
  It is closed source and shipped as a zip from its itch.io page, so every
  reference below names a method and an IL offset in the CSpect.exe of 3.3.1.0.
  Type and member names in that build are obfuscated and the string literals sit
  XOR encoded in one 18146 byte blob, decoded at class load by b[i] ^ i ^ 0xAA.
  ref: CSpect.exe 3.3.1.0, ReadMe.txt:9-11

  The machine carries no built-in ROM. A cold reset either loads the Next ROMs
  or allocates them zero filled, 65536 bytes for the ROM banks and 8192 each for
  the DivMMC and Multiface ROMs. The loading branch runs when the Next ROM flag
  is set, which -nextrom and -fw do, which -mmc= does when its argument is an
  existing file, and which a positional argument does when it opens as a FAT
  image.
  ref: CSpect.exe 3.3.1.0 a.H::A(bool) IL_01fe-IL_023c, A.h::A(string[])
       IL_012b-IL_0197, A.h::A(string[]) IL_0697-IL_070e, A.h::a(string[])
       IL_0131-IL_0150

  The ROMs live inside the SD card image, not beside the executable. e() opens
  the image through SDCardAccess.SDCard.Open and pulls each ROM out with
  SDCard.LoadFile, whose directory walk lowercases both sides of the comparison,
  so the spelling of these paths carries no weight. Memory pages enNextZX.rom as
  four 16K banks and the other two as their first 8192 bytes.
  ref: CSpect.exe 3.3.1.0 a.H::e() IL_000b-IL_00f7, a.H::N(int32)
       IL_0051-IL_00b1, SDCardAccess.dll SDCard.cs:457-490, SDCard.cs:624-635

  ES-DE launches it as mono CSpect.exe -zxnext -mmc=./ <rom> from the game
  folder. An -mmc= naming a directory leaves the Next ROM flag clear, so the
  .nex file runs against the zero filled banks while the bundled esxDOS plugin
  answers RST $08 out of that directory.
  ref: es_systems.xml zxnext, A.h::A(string[]) IL_0697-IL_06f7, esxDOS.dll
       CRST8.cs:286-302

  A positional argument ending in none of nex, sna, snx, rom or fw is taken for
  a card image, and when no file sits at that path CSpect offers to fetch one:
  it reads https://zxnext.uk/hosted/ for the first href holding 8gb, unzips it
  and copies the single .img inside to the path that was asked for. The path is
  then accepted only if its MBR and boot sector read. A .rom argument goes into
  a 128 KB buffer entered at 0x6000 instead, and a .fw argument is unpacked
  through the TBBLUE.FW header.
  ref: A.h::a(string[]) IL_00a6-IL_012c, A.h::b(string), A.h::B(string, string),
       a.d::C(string) IL_0086-IL_01db

  What CSpect writes rather than reads: cspect_win.dat under -r for the window
  placement, cspect.log for the session log, the F5 screenshots, and the -wad=
  container under LocalApplicationData/CSpect, which is created when it does not
  exist. The debugger reads the symbol and map files that -map=, -zmap=, -clst=,
  -z88dk and -pasta80 name, all of them output of the user's own assembler. The
  Windows build probes its audio runtime with LoadLibrary("openal32.dll") and
  offers to run the bundled oalinst.exe when that answers zero.
  ref: B.E::e(), B.E::E(), a.V::.ctor(string), A.y::A(), A.y::A(bool, bool),
       A.g::A(), A.h::a(string[]) IL_02dc-IL_034f

files:
  - name: enNextZX.rom
    path: "machines/next/enNextZX.rom"
    system: sinclair-zx-spectrum-next
    required: true
    min_size: 65536
    description: "NextZXOS and BASIC ROM"
    note: >-
      Paged as four 16K banks, so anything shorter than 65536 bytes leaves the
      top bank unreadable. The image failing to hold it ends the process through
      Environment.FailFast. Bytes 6 and 7 carry the NextZXOS version as
      b[6] + ((b[7] & 0x0f) << 8), and a value of 518 or less clears the flag
      that arms the program counter watch the CPU runs before each instruction.
    source_ref: "CSpect.exe 3.3.1.0 a.H::e() IL_00bd-IL_00c9, a.H::e() IL_0102-IL_0149, a.H::N(int32) IL_0051-IL_0086, A.h::a(string[]) IL_0637-IL_0644"

  - name: enNxtmmc.rom
    path: "machines/next/enNxtmmc.rom"
    system: sinclair-zx-spectrum-next
    required: true
    min_size: 8192
    description: "DivMMC ROM, the esxDOS layer over the SD card"
    note: >-
      Read into the 8K DivMMC bank. Its absence ends the process through the
      same Environment.FailFast as enNextZX.rom, except under -fw, where the
      test is skipped because TBBLUE.FW replaces both reads.
    source_ref: "CSpect.exe 3.3.1.0 a.H::e() IL_00da-IL_00e6, a.H::e() IL_010a-IL_012e, a.H::N(int32) IL_0087-IL_0097"

  - name: enNextMf.rom
    path: "machines/next/enNextMf.rom"
    system: sinclair-zx-spectrum-next
    required: false
    min_size: 8192
    aliases: ["enNextMF.rom"]
    description: "Multiface ROM"
    note: >-
      Read into the 8K Multiface bank with no test of any kind, so a card
      without it boots and runs. The bank read indexes the array directly,
      which faults the moment the Multiface is paged in.
    source_ref: "CSpect.exe 3.3.1.0 a.H::e() IL_00eb-IL_00f7, a.H::N(int32) IL_00a1-IL_00b1"

  - name: TBBLUE.FW
    system: sinclair-zx-spectrum-next
    required: false
    description: "FPGA core firmware"
    note: >-
      Read from the root of the card under -fw only, in place of the three ROMs.
      Word 0 of its header gives the payload offset as (n + 1) * 512 and word 1
      the payload length as n * 512, and those bytes are written to memory from
      0x6000. A .fw file named on the command line takes the same route.
    source_ref: "CSpect.exe 3.3.1.0 a.H::e() IL_0016-IL_00bb, A.h::A(string[]) IL_0164-IL_0197, a.d::C(string) IL_014b-IL_01db"

  - name: "<sdcard>.img"
    system: sinclair-zx-spectrum-next
    required: true
    description: "ZX Spectrum Next SD card image"
    unsourceable: >-
      A FAT image the user builds or downloads, under whatever name is passed to
      -mmc= or given as the positional argument. CSpect fetches the current one
      from https://zxnext.uk/hosted/ on demand, and the machine writes to it.
    note: >-
      The only route to the ROMs above. SDCard.Open reads its MBR and boot
      sector, which is also the test that decides whether a positional argument
      is a card or a game, and the DivMMC opens the same path read write as its
      card. A second image mounts on the second slot through -sd2=.
    source_ref: "CSpect.exe 3.3.1.0 a.H::e() IL_000b-IL_0015, A.h::A(string) IL_0000-IL_00b6, A.h::A(string[]) IL_0697-IL_0773, B.R::.ctor(string), SDCardAccess.dll SDCard.cs:600-635"