This page was last modified 14:36, 26 May 2023 by Mars2000you. Based on work by Takamichi and Sylvester and others.


"X-BASIC" aka "MSX-BASIC KUN", "KUN BASIC" or "TURBO BASIC" is a run-time compiler for MSX-BASIC that is commonly used to speed up existing MSX-BASIC programs and create demos and games.


There are three versions of this compiler, the first two versions are officially released on cartridge, but hacked binary versions were also available:

  • 1.0 - MSX-BASIC Kun (1986)
  • 2.0 - MSX-BASIC Kun Plus (1989)
    • supports the new screen mode (SCREEN 10-12) of MSX2+
    • supports VDP functions for registers added in V9958
    • supports scroll instruction (SET SCROLL)
    • a sample disc is added
  • 2.1 - MSX-BASIC Kun Turbo (1992)
    • supports multiplication instructions for the new CPU R800 in MSX turbo R computers
    • supplied as a disk instead of a ROM cartridge

Version 1.0 is included in the MSX2 Talent TPC-310 computer as TURBO BASIC.

A slightly modified version of MSX-BASIC Kun Plus is included in the MSX2+ Sanyo PHC-70FD and PHC-70FD2 computers with internal disk drive(s). It comes with an extra instruction, CALL BC that initialises KUN BASIC.

MSX-BASIC Kun Turbo is also included in the GR8NET combo cartridge as a ROM.


According the used version, X-BASIC adds 6 or 7 instructions to MSX-BASIC.


  • For the instructions that begin with CALL, you can replace CALL by _ (the underscore character). A space is not required after this character.
  • Sometimes CALL TURBO OFF and CALL TURBO ON were renamed by the coders of the MSX scene in their products (games, demos, disk magazines, tools).
Instruction Generation Versions Remarks
'#C MSX2 1.0 - 2.0 - 2.1
'#I MSX1 1.0 - 2.0 - 2.1
'#N MSX1 1.0 - 2.0 - 2.1
CALL BC MSX2+ 2.0 Only on MSX2+ Sanyo with internal disk drive(s)
CALL RUN MSX1 1.0 - 2.0 - 2.1
CALL TURBO OFF MSX1 1.0 - 2.0 - 2.1
CALL TURBO ON MSX1 1.0 - 2.0 - 2.1


Note: the above documentation is included with MSX-BASIC Kun, so not sure why they say that the REM commands (#C, #I, #N) are new

Pages in category "X-BASIC"

The following 2 pages are in this category, out of 2 total.