fxlibc: The FX C Library

This directory contains the sources of the FxLibc Library. See CMakeLists.txt to see what release version you have.

The FxLibc is the standard system C library implementation for all Casio fx calculators, and is an important part of what makes up programs on these devices. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective-C; the runtime facilities of other programming languages use the C library to access the underlying operating system.

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Dependencies

FxLibc requires a GCC compiler toolchain the PATH to build for any calculator. You cannot build with your system compiler! The tutorial on Planète Casio builds an sh-elf toolchain that supports all models using multilib. See also Lephenixnoir/sh-elf-gcc.

For Vhex targets, the headers of the kernel are also required (but not for gint; the fxlibc is installed before gint).

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Building and installing FxLibc

FxLibc supports several targets:

• Vhex on SH targets (vhex-sh)
• CASIOWIN for fx-9860G-like calculators (casiowin-fx)
• CASIOWIN for fx-CG-series calculators (casiowin-cg)
• gint for all calculators (gint)

Each target supports different features depending on what the kernel/OS provides.

For automated gint/fxSDK setups using GiteaPC is recommended. The instructions below are for manual installs.

Configuration

Configure with CMake; specify the target with -DFXLIBC_TARGET. For SH platforms, set the toolchain to cmake/toolchain-sh.cmake.

You can either install FxLibc in the compiler's include folder (for Vhex), or another folder of your choice (eg. the fxSDK sysroot). If you choose non-standard folders you might need -I and -L options to use the library.

# Install in the compiler's include folder
% PREFIX="$(sh-elf-gcc -print-file-name=.)"
# Install in the fxSDK sysroot
% PREFIX="$(fxsdk path sysroot)"
# Custom target
% PREFIX="$HOME/.sh-prefix/"
# For gint, do not specify anything, the fxSDK will be used dynamically

Example for a static Vhex build:

% cmake -B build-vhex-sh -DFXLIBC_TARGET=vhex-sh -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-sh.cmake -DCMAKE_INSTALL_PREFIX="$PREFIX"

Or for a traditional gint/fxSDK build:

% cmake -B build-gint -DFXLIBC_TARGET=gint -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-sh.cmake

Build and install

Build in the directory specified in cmake -B.

% make -C build-X
% make -C build-X install

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Contributing

Bug reports, feature suggestions and especially code contributions are most welcome.

If you are interested in doing a port, or want to contribute to this project, please, try to respect these constraints:

• Document your code.
• One function per file (named like the function).
• Use the same formatting conventions as the rest of the code.
• Only use hardware-related code (DMA, SPU, etc) in target-specified files when the target explicitly supports it.

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Using FxLibc

Include headers normally (#include <stdio.h>); on SH platforms where sh-elf-gcc is used, link with -lc (by default the -nostdlib flag is used for a number of reasons).

If you're installing in a custom folder, you also need -I "$PREFIX/include" and -L "$PREFIX/lib". If you're installing in the GCC install folder, you don't need -I but you still need the -L as the default location for libraries is at the root instead of in a lib subfolder.

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Licences

This work is licensed under a CC0 1.0 Universal License. To view a copy of this license, visit: https://creativecommons.org/publicdomain/zero/1.0/legalcode.txt Or see the LICENSE file.

FxLibc also includes third-party code that is distributed under its own license. Currently, this includes:

• A stripped-down version of the TinyMT random number generator (GitHub repository) by Mutsuo Saito and Makoto Matsumoto. See 3rdparty/tinymt32/LICENSE.txt.
• A stripped-down version of the Grisu2b floating-point representation algorithm with α=-59 and γ=-56, by Florian Loitsch. See 3rdparty/grisu2b_59_56/README for details, and the original code here.

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Special thanks to

• Lephenixnoir - For all <3
• Kristaba - For the idea with the shared libraries workaround !