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Introduction - C.Basic, a part of C:Basic Project

If you feel your Casio Basic programs are not running fast enough, C.Basic can free you of that frustration.

Get started with genuine Casio Basic program, then extended commands that C.Basic alone perform.

  • Currently C.Basic (Basic interpreter) runs on fx-9860G Series (SH3) or later Graphing Calcs.
    • C.Basic for FX supports fx-9860G Series (SH3), fx-9860GII Series (SH4A),
      and Graph 35+USB/35+EII/75/85/95 (SD).
    • C.Basic for CG supports PRIZM fx-CG10, fx-CG20, fx-CG50 and Graph90+E.
  • C.Basic will evolve into a Casio Basic compiler "C:Basic", which will run programs much faster than C.Basic (10 times from the looks of it).


All the instruction of C.Basic are in following text files included in C.Basic disribution package.

C.Basic is a part of C:Basic Project. The Project C:Basic will provide Add-In Casio Basic Interpreter and Compiler. At this moment C.Basic (single dot) a Basic interpreter is released.

C.Basic is supplied as an Add-In program for fx-9860G and fx-9860GII Series, also fx-CG Series.

In the future C:Basic (double dots, colon) will include compiler version.

What is C.Basic?

C.Basic is designed for Fast, compatible with genuine Casio Basic and also bringing in some of good features of fx-5800P.

C.Basic for FX uses program file (*.g1m) or C.Basic for CG uses program file (*.g3m), these should be stored in storage memory. On the other hand Genuine Casio Basic uses also g1m or g3m file but these should be stored in main memory. A program source using only compatible commands can run in both of C.Basic and genuine Casio Basic.

Add-In Casio Basic Interpreter (& Complier)
copyright(c)2015 by sentaro21
e-mail to auther: sentaro21(at)pm.matrix.jp
e-mail to administrator & author of this site: Krtyski.egadget(at)gmail.com


  • C.Basic is mostly compatible with genuine Casio Basic.
  • Prgoams run at least 10 times faster in C.Basic.
  • C.Basic's File List and Editor are easier to use than the usual ones.
  • Can execute programs from storage memory as default, optionally from SD or main memory, and supports sub-folder structures. [updated on 14th Jun., 2019]
  • Some Casio Basic commands are extended for more features.
  • Newly-implemented comamnds for more powerful and flexible programming.


  • C.Basic does not cover all of the origianl Casio Basic commands.
  • Calculations do not yield the same results as the usual interpreter because C.Basic use double-precision floating point instead of fixed-point BCD.
  • C.Basic stores PICT files in storage memory, hence using them is slower (at least until version 0.87 which uses the heap area from the main memory).
  • There must be some bugs, unfortunately (^^; Please provide us with a bug report if you find any.

Almost compatible with vanilla Casio Basic

Flawless compatibioity is our goal, but some differences are intentional;

  • "?" and "?→" imput commands are displayed on a single line. Dysplaying a string longer than 21 charactors will result in horizontal scroll instead of line wrap.
  • When a graphing sketch commands is followed by the milti- statement command ":", the screen is not refreshed.
  • Program running time is displayed when the program ends. This function can be triggered in the setup page.
  • A Comment delimiters " ' " are allowed before carriage returns, Disp (output),   (output), and ":" (Multi-statement Command) can be included in the comment string. 

C.Basic also takes in user-friendly feature of fx-5800P; 

  • C.Basic supports a "?A" command as fx-5800P, as opposed to the supporting Graphing Calcs which only support "?→A".
  • String output command " " is fully compatible with fx-5800P thus a bit deferent from the supporting Graphing Calcs. See Topics for details. 


We don't believe that C.Basic could damage your calculator, but the mail memory could still be unexpectedly damaged or destroyed, which would require a hole memory reset. Hence it is strongly recommended that you backup your main and storage memory data. Please be aware that you should only use C.Basic at your sole risk.

Disclaimer of Warranty

Use of C.Basic and C:Basic (hereinafter SOFTWARE) is at user’s sole risk. All materials, information, products, software, programs and service provided “as is”, with no warranties or guarantees whatsoever. Creators of SOFTWARE and support team who provide support documents, support web site, information and sample programs (hereinafter DEVELOPMENT TEAM) expressly disclaim to the fullest extent permitted by law, all express, implied, statutory, and other warranties, guarantees, or representations, including, without limitation, the warranties of merchantability, fitness for a particular purpose, and non-infringement of proprietary and intellectual property rights. Without limitation, DEVELOPMENT TEAM makes no warranty or guarantee that development of SOFTWARE will be uninterrupted, timely, secure, or error-free. 


Download - Get Latest Version

C.Basic for FX - fx-9860G, fx-9860GII Series and Graph 35+USB/35+EII/75/85/95 (SD)

C.Basic for CG - fx-CG10, fx-CG20, fx-CG50 and Graph 90+E


Installation of C.Basic

  1. Download C.Basic package at "C.Basic for FX : Get Latest Version" or "C.Basic for CG: Get Latest Version" page.
  2. Transfer Add-In file to storage memory of your Graphing Calc.
    1. Transfer CBasic.g1a file to storage memory of your fx-9860G or fx-9860GII Series using PC link software FA-124A. See below.
    2. Transfer CBCGxxx.g3a file (xxx stands for version number) to storage memory of your fx-CG Series by simply using explorer. fx-CG series is recognized as an external drive. See below.
  3. To start up C.Basic, press [MENU] key and select C.Basic icon.
  4. To check version of C.Basic, press [SHIFT] [MENU] [F6](Ver.), then version is shown.
  5. When the version is same as what you want to install, the installation has been done correctly.
  6. To return back to File List, press [EXIT] and [EXIT] again.
  7. CBasic.g1a and CBCGxxx.g3a are rather large file, so Optimization of memory is recommended to do. Press [MENU], select MEMORY icon, press [EXE] and press [F5] (Optimization).

Using the PC link software (FA-124) for fx-9860G / fx-9860GII Series

FA-124 is a PC link software which is included in the package of fx-9860G or fx-9860GII Series. For detailed operation please refer its manual. Recently CD is notincluded in a distribution package, download FA-124 from Casio Worldwide Education Website.

Copy CBASIC.g1a to Storage Memory in right pane of FA-124. Connect fx-9860G or fx-9860GII Series to PC using USB cable. Left pane shows files in your calc. Transfer CBASIC.g1a in storage memory in right pane to left pane in storage memory.

Font folder and FontEdit folder should also be transfered to the Storage Memory if you want to use extended fonts.


When available storage memory comes low and you want to update C.Basic, it's recommended to delete CBASIC.g1m at first, perform Optimization of storage memory, then transfer latest version of CBASIC.g1m.

For detailed instructions, please refer to instruction manual of FA-124.

Note: FA-124 bug info. - files may be destroyed when multiple files are copied at once in right pane. Do not copy multiple files at once to right pane from left pane or outside of FA-124A. When get backup files into right pane of FA-124, you should trasfer the files back to calc and check their functionality for sure. If they are OK, then your backup files are OK.

Using Explorer for fx-CG10, fx-CG20 and fx-CG50

Connecting fx-CG Series to your PC with USB cable and open Exporler, then fx-CG is shown as an external drive.

Root of the external drive is storage memory of fx-CG Series calc. Transfer CBCGxxx.g3a (xxx stans for version number of C.Basic for CG) to Storage Memory shown as root of the extrenal drive. @Font folder and FontEdit folder should also be transfered to the Storage Memory if you want to use extended fonts.


Starting Up C.Basic

To start up C.Basic, press [MENU], select C.Basic icon then press [EXE]. 

You may have program files (g1m or g3m file) in your PC, simply transferring the program files to graphing calc then these files can easily run on C.Basic. There are several ways to transfer the program files from PC to graphing calc.

Using the PC link software (FA-124) for fx-9860G / fx-9860GII Series

If Program File (*.g1m) has been made or downloaded and stored in your PC, transfer the program files to your calc using FA-124. Latest version of C.Basic for FX can run program file in main memory as well as storage memory.

If genuine Casio basic program files have been stored in PC, you can run them on latest C.Basic by setting up Storage Mode as Main Memory mode without transfering the files to storage memory. 

Using Explorer for fx-CG10, fx-CG20 and fx-CG50

If Program File (*.g1m and *.g3m) has been made or downloaded and stored in your PC, transfer the program files to your calc using Explorer. Latest version of C.Basic for CG can run program file in main memory as well as storage memory. Genuine Casio Basic Program Fles are in @MainMem/PROGRAM folder. 

If genuine Casio basic program files (*.g1m and *.g3m) have been stored in PC, you can run them on latest C.Basic by setting up Storage Mode as Main Memory mode without transfering the files to storage memory.

Copy files from storage to main memory - pre-installed memory manager

  • To start up the memory manager, press [MENU], select Memory manager icon and press [EXE].
  • Press [F1] to display the contents of the main memory.
  • Move the cursor down to <PROGRAM> and press [EXE]. You should now be seeing the list of all Casio Basic programs currently installed for the usual interpreter.
  • Select the program file that you want to copy.
  • Press [F1] (SEL) and [F2](COPY).
  • Select "ROOT", press [EXE]; the calculator will ask you fo a file name.
  • Enter an appropriate file name or just "A" then press [EXE].
  • Press the [MENU] key to go back to the MAIN MANU
  • Start C.Basic.
  • In File List select the name you just entered, press [F6] and then [F2] (REN).
  • You will be prompted with [Rename File Name?], and the original file name will be displayed (even though you typed in "A"), press [EXE].
  • Now the file name has been corrected.



To investigate and implement internal specification, "SuperH-based fx calculators (version 20)" gave useful information.

For file handling in C.Basic, "Wsc & Fvm V1.2 - Casio Fx-9860 Series On-calc C Compiler" gave useful information.

For detailed feature and function of original Casio Basic, following site is referenced;
"e-Gadget - Programming Calculator (プログラム関数電卓)" by Krtyski
(almost contents are in Japanese).

I am grateful for everyone's cooperation.

by sentaro21


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This software is free software, in accordance with GPL Ver 2.


inserted by FC2 system