Newlib - a C Standard Library for Casio Calulators

Motivation

Until now there was no complete C standard library (aka libc) available for the Casio calculators. Although some parts of this library have been provided by fxlib and gint, there was no libc implementation complying with the standard and compatible with the sh3eb architecture ready to use.

To change that, I decided to port newlib to the Casio CPU. Newlib is an alternative libc implementation intended for use on embedded systems.

Alpha

Follow this link and click the download button in the top right corner:

v1.1

Installation

For a complete tutorial on how to setup a toolchain for Casio calculators, see Compiler sous Linux avec GCC.

To build newlib, you first need binutils and gcc for the target sh3eb-elf. Make sure to configure gcc with the arguments --with-newlib --without-headers.

Now you can install newlib. Simply call configure and make:

../newlib-cygwin/configure --target=sh3eb-elf --prefix=...
make
make install

Afterwards, you have to build gcc again with the argument --with-newlib.

For a more detailes tutorial about how to setup newlib in general, see this more detailed turorial.

Features for Casio fx9860g calculators:

• C standard library libc
  • printf implementation to print text to the display
  • Dynamic allocation of memory using malloc and free
  • Memory manipulation using memcpy, memcmp, memset etc.
  • String manipulation using strcpy, strcmp, strstr, strtok
  • ...
• Math library libm
  • Floating point arithmetics
  • ...
• Automatic library and include path recognition after installation
• Basic Casio features:
  • implementation of GetKey, Bdisp_AllClr_DDVRAM, Bdisp_PutDisp_DD, Print and locate without fxlib (but you can use it if you want)

Further information

Upstream Repository

Newlib provides releases in their ftp directory and their code on their git repository. I try to rebase my fork regulary to their master branch to keep it up-to-date.

The target sh3eb-elf

There is a great explanation on the naming convention of targets. To really understand what sh3eb-elf means, I'll boil it down for you:

To compile code for our Casio calulator, we need to tell newlib where we want to run the code. In our case, the target's name is sh3eb-elf.

sh is here short for the SuperH processor architecture. (Fortunately, newlib supports SuperH the by default.)

To be more specific, sh3 is a 32-bit CPU architecture of the SuperH family. Furthermore, eb stands for the big endian format (that indicates the byte order used for multi-byte variables). Usually a target also indicates a vendor which in this case is unknown. Lastly, the end of the target's name is elf (which is usually the kernel). Here, we have no kernel (and hence no operating system) at all.

For newlib, the target sh3eb had to be specifically added.