72 lines
2.5 KiB
Markdown
72 lines
2.5 KiB
Markdown
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# OpenLibm
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[](https://codecov.io/gh/JuliaMath/openlibm)
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[OpenLibm](https://openlibm.org/) is an effort to have a high quality, portable, standalone
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C mathematical library ([`libm`](http://en.wikipedia.org/wiki/libm)).
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It can be used standalone in applications and programming language
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implementations.
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The project was born out of a need to have a good `libm` for the
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[Julia programming language](http://www.julialang.org) that worked
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consistently across compilers and operating systems, and in 32-bit and
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64-bit environments.
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## Platform support
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OpenLibm builds on Linux, macOS, Windows, FreeBSD, OpenBSD, NetBSD, and
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DragonFly BSD. It builds with both GCC and clang. Although largely
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tested and widely used on the x86 and x86-64 architectures, OpenLibm
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also supports arm, aarch64, ppc64le, mips, wasm32, riscv, s390(x) and
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loongarch64.
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## Build instructions
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### GNU Make
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1. Use GNU Make to build OpenLibm. This is `make` on most systems, but `gmake` on BSDs.
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2. Use `make USEGCC=1` to build with GCC. This is the default on
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Linux and Windows.
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3. Use `make USECLANG=1` to build with clang. This is the default on OS X, FreeBSD,
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and OpenBSD.
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4. Use `make ARCH=wasm32` to build the wasm32 library with clang.
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5. Architectures are auto-detected. Use `make ARCH=i386` to force a
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build for i386. Other supported architectures are i486, i586, and
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i686. GCC 4.8 is the minimum requirement for correct codegen on
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older 32-bit architectures.
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**Cross Build**
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Take `riscv64` as example:
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1. install `qemu-riscv64-static`, `gcc-riscv64-linux-gnu`
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2. Cross build:
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```sh
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ARCH=riscv64
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TRIPLE=$ARCH-linux-gnu
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make ARCH=$ARCH TOOLPREFIX=$TRIPLE- -j
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make -C test ARCH=$ARCH TOOLPREFIX=$TRIPLE- -j
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```
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3. Run test with qemu:
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```sh
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qemu-$ARCH-static -L . -L /usr/$TRIPLE/ test/test-float
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qemu-$ARCH-static -L . -L /usr/$TRIPLE/ test/test-double
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```
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### CMake
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1. Create build directory with `mkdir build` and navigate into it with `cd build`.
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2. Run CMake to configure project and generate native build system with `cmake /path/to/openlibm/`
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or generate project with build system of choice e.g. `cmake /path/to/openlib/ -G "MinGW Makefiles"`.
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3. Build with the build system with `cmake --build .`.
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Default CMake configuration builds a shared library, this can easily be configured using
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[BUILD_SHARED_LIBS](https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html)
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configuration option.
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## Acknowledgements
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PowerPC support for openlibm was graciously sponsored by IBM.
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