gint project

gint (pronounce 'guin') is a low-level library for fx-9860G calculators. It provides a mostly free-standing runtime support for the platform, and can be used to develop add-ins under Linux along with the gcc toolchain (sh3eb-elf target) and the fxSDK.

gint is free software: you may use it for any purpose, share it, modify it and share your changes. No credit of any kind is required, though appreciated.

Programming interface

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

• Extensive keyboard control, including replication of the system behavior for office applications and event-driven decisions for games
• Hardware timers running at over 10 MHz, allowing microsecond-level control
• Unlimited mappings of callbacks to Real-Time Clock events (requires build)
• Access to processor registers for debugging information, determination of processor speed (overclock is on the TODO list), backlight management...

The library also offers powerful higher-level features:

• A gray engine that works by rapidly swapping monochrome images
• Blazingly fast drawing functions when working with the fxSDK (10 times faster image rendering that MonochromeLib)
• C Standard functions such as the printf() family

Interrupt handler

The interrupt handler is the lowest-level part of the library. It directly accesses the peripheral modules and workarounds the system to perform keyboard analyzes directly on hardware or timer management.

gint does not allow user programs to use their own handlers, but it allows them to complete the original handler if they want to use interrupts that are not supported by the library. It is also possible to map various interrupt-driven events to user-provided callbacks using the API, which is not allowed by the operating system. This is particularly useful for timers and the Real-Time Clock (the 16 Hz interrupt can be used to run a physical engine, while the 1 Hz interrupt can be used in a real-time management game).

Building and installing

To build and install gint, you will need the following components:

• The sh3eb-elf toolchain linked somewhere in the PATH
• The fxSDK installed and available in the PATH

The classical way to build gint is to enter a terminal and use the usual:

$ ./configure
$ make
# make install

This will build the all-lib target and install the following components in the storage folder of the fxSDK:

• libgint.a, the gint library
• libc.a, the partial standard library
• The libgint headers for development

When explicitly running target all, the following additional files will be generated in the working directory:

• gintdemo.g1a, a test application
• gintdbg.g1a, a non-gint application used for debugging in case gint crashes

The usual clean, mrproper, and distclean rules will clean the directory. There are configuration options, which can be obtained using ./configure --help. Most of them customize size limits, if a project needs to extend them. The true free-standing program may build the library using the --no-syscalls switch, but some features will be disabled (dynamic allocation...).

Source organization

gint is made of modules. Each module has one or more of the following component files:

• A header file in /include
• An internal header file in /include/internals
• Single-function source files in /src/module: to avoid linking against the whole library, some functions have their own object files. Their names are those of the functions.
• Other source files in /src/module: contain multiple functions that always work together, or are lightweight enough not to be separated. Their names often begin with module_.
• Other files in /src/module: the display module contains a font.

The demo application is in the demo folder.