OpenLibm/README.md

# Soft-FP sh3eb port of OpenLibm

This is a fork of [OpenLibm](https://github.com/JuliaMath/openlibm) with support for the sh3eb architecture, intended for add-in programming on SuperH CASIO calculators.

## Installing with GiteaPC

This library can be installed automatically as part of the fxSDK with [GiteaPC](https://gitea.planet-casio.com/Lephenixnoir/GiteaPC):

```bash
% giteapc install Lephenixnoir/OpenLibm
```

## Building manually

You will need a GCC toolchain built with `--target=sh3eb-elf`, such as the [`sh-elf-gcc`](https://gitea.planet-casio.com/Lephenixnoir/sh-elf-gcc) commonly used on Planète Casio.

You can install directly in the internal folder of your compiler, or somewhere else if you have a more detailed setup.

```bash
# Example 1: Use the compiler's internal folder
% COMPILER_DIR="$(sh-elf-gcc --print-file-name=.)"
% LIBDIR="$COMPILER_DIR"
% INCDIR="$COMPILER_DIR/include"
# Example 2: Using the fxSDK's custom setup
% LIBDIR="$(fxsdk path lib)"
% INCDIR="$(fxsdk path include)"
```

You can then build and install the static library and the headers.

```bash
% make USEGCC=1 TOOLPREFIX=sh-elf- AR=sh-elf-ar CC=sh-elf-gcc \
    libdir="$LIBDIR" includedir="$INCDIR" \
    install-static-superh install-headers-superh
```

The `-superh` targets differ from the the normal targets in the following ways:

* `install-static-superh` also creates a symlink `libm.a -> libopenlibm.a`.
* `install-headers-superh` installs directly in `$LIBDIR` instead of `$LIBDIR/openlibm` since OpenLibm headers reference each other without that prefix and enforcing the correct `-I` in every project is quite painful. In addition, it skips internal and non-SuperH headers.

## Using the library

Include the headers `<openlibm_complex.h>`, `<openlibm_fenv.h>` and `<openlibm_math.h>`. Or, if you are using a suitable libc like [fxlibc](https://gitea.planet-casio.com/Vhex-Kernel-Core/fxlibc/), include directly the standard headers `<complex.h>`, `<fenv.h>` and `<math.h>`.

Link with `-lm`. In a Makefile, update your `LDFLAGS`:

```
LDFLAGS += -lm
```

In CMake, use [`target_link_libraries()`](https://cmake.org/cmake/help/latest/command/target_link_libraries.html):

```cmake
target_link_libraries(<TARGET> PUBLIC -lm)
```

## README and Licensing

See the original README file in [README-OpenLibm.md](README-OpenLibm.md). OpenLibm contains code covered by various licenses, see [LICENSE.md](LICENSE.md).