gint project

gint (pronounce 'guin') is a development system for Casio fx-9860G II and fx-CG 50 calculators. It provides a mostly free-standing runtime and is used to develop add-ins under Linux, along with specialized GCC toolchains and the fxSDK.

gint is a modular kernel that implements its own drivers for the calculator's hardware, overriding the operating system and its syscalls. It is a drop-in replacement from fxlib, with which it is mostly incompatible. gint exposes a new, richer API to manipulate the hardware and take advantage of the full capabilities of the machine.

This is free software: you may use it for any purpose, share it, and modify it as long as you share your changes. Credit is not required, but please let me know!

Programming interface

Because of its free-standing design, gint's API provides direct and efficient access to the low-level MPU features, among which:

• Multi-key management with event systems suitable for games
• Hardware timers with sub-millisecond and sub-microsecond resolution
• Fast screen drivers with DMAC on fx-CG 50
• Efficient and user-extendable interrupt management

The library also offers powerful higher-level features:

• An enhanced version of the system's GetKey() and GetKeyWait()
• A gray engine that works by rapidly swapping monochrome images on fx-9860G II
• Blazingly fast drawing functions when working with the fxSDK (image rendering is 10 times faster than MonochromeLib)
• Integrated font management with the fxSDK
• Integration with a Newlib port by Memallox (WIP)

Building and installing gint

You can choose to build gint for fx-9860G II (monochrome calculators, aka Graph 85 family), fx-CG 50 (color calculators, aka Prizm or Graph 90 family), or both. There are a few dependencies:

• A suitable GCC toolchain in the PATH. You can absolutely not build gint with your system compiler!
  • The tutorial on Planète Casio builds an sh-elf that works everywhere
  • For fx-9860G II, sh3eb-elf is strongly advised
  • For fx-CG 50, sh4eb-elf (with -m4-nofpu) is slightly better but sh3eb-elf is completely fine
• The fxSDK installed and available in the PATH. You will need fxconv to build gint, and if you intend to develop add-ins for fx-9860G II, you probably want fxg1a as well. All these tools are built by default.

fx-CG 50 developers probably want a g3a wrapper as well; the reference implementation is tari's mkg3a. This is needed at the very last compilation step to create the g3a file. On Arch Linux, you can use the AUR/mkg3a package maintained directly by Tari.

The build process is detailed below for both platforms, the principle is the same. You can build both targets at the same time by reading the two sections.

By default gint will be installed in the appropriate compiler folder, which is $PREFIX/ for libraries and linker scripts, and $PREFIX/include/gint/ for headers, where PREFIX is obtained by running ${toolchain}-gcc --print-search-dirs and reading the line that starts with install:. You can change this with the --prefix configure option.

Building for fx-9860G II

Create a build directory and configure in it:

% mkdir build.fx && cd build.fx
% ../configure --target=fx9860g

Then build the source and install the library files to the selected directory. You might need root access if you selected a target directory owned by root with --prefix, or if you built your compiler as root.

% make
% make install

Building for fx-CG 50

Create a build directory and configure in it. The default toolchain is sh4eb-elf, if you wish to build with sh3eb-elf, you need to add a command-line option --toolchain=sh3eb-elf.

% mkdir build.cg && cd build.cg
% ../configure --target=fxcg50

Then build the source and install the library files to the selected directory.

% make
% make install

Using gint

To use gint as your runtime environment, the bare minimum is:

• Build with -ffreestanding;
• Link with -T fx9860g.ld and -lgint-fx on fx-9860G;
• Link with -T fxcg50.ld and -lgint-cg on fx-CG 50.

If you don't have a standard library such as Memallox's port of newlib, you also need -nostdlib. I typically use -m3 -mb or -m4-nofpu -mb to specify the platform, but that may not even be necessary.

Typically you might want to do this with the fxSDK, which hides most of the details and makes it easy to roll add-ins.