A downloadable game

OpenSE BASIC is an open source replacement firmware for the ZX Spectrum and clones that includes many improvements over the original, while retaining a high level of compatibility. Some of the highlights are:

  • Overall fastest version of Sinclair BASIC - fully optimized for speed.
  • Fastest and most user-friendly editor - with additional editing commands.
  • AY support including pseudo-interrupt driven sound.
  • ULAplus support including a default palette and new commands.
  • 8-bit character set support including printing characters 24-31.
  • Direct machine code calls.
  • BASIC access to LDIR.
  • Hex and Octal number entry.
  • Decimal to Hex string conversion.
  • Intelligent error trapping - OK and STOP are not errors.
  • More room for BASIC programs and line numbers up to 16383.
  • Improved SCREEN$ handling for UDGs and 8-bit character sets.
  • Improved floating-point library - faster and more accurate.
  • Remains compatible with the majority of Spectrum software and hardware.
  • Ability to use reserved words as variable names during tokenization.

  • Version 3.2.0 has the following changes from the previously released 3.1.2:

    • Compatibility improvements:
      • Replaced Geneva Mono font with Jupiter81 font.
      • Restored UDGs to original location.
      • Changed boot colors to black on white.
      • Swapped bytes at 04D0 / 04D1 to support tape traps.
    • Reincorporated external data into the main assembly file.
    • Switched default compiler back to Pasmo.
    • Verified entry points against esxDOS 0.8.5 disassembly.

    Version 3.2.1 has the following changes:

    • Note table calculated with higher precision.
    • NMIADD system variable moved to avoid a clash with disk systems including esxDOS.


    Virtual tape support under esxDOS is unstable at best.


    seBasic321.asm 194 kB
    seBasic321.rom 16 kB
    OpenSE BASIC.pdf 475 kB
    OpenSE mini logo 11 kB