OpenLibm is an effort to have a high quality, portable, standalone C mathematical library (libm). It can be used standalone in applications and programming language implementations.

The project was born out of a need to have a good libm for the Julia programming langage that worked consistently across compilers and operating systems, and in 32-bit and 64-bit environments.

OpenLibm builds on Linux, Mac OS X, Windows, FreeBSD, OpenBSD, and DragonFly BSD. It builds with both GCC and clang. Although largely tested and widely used on the x86 and x86-64 architectures, OpenLibm also supports arm, aarch64, ppc64le, and mips.

1. Use GNU Make to build OpenLibm. This is make on most systems, but gmake on BSDs.
2. Use make USEGCC=1 to build with GCC. This is the default on Linux and Windows.
3. Use make USECLANG=1 to build with clang. This is the default on OS X, FreeBSD, and OpenBSD.
4. Use make ARCH=wasm32 to build the wasm32 library with clang. Requires clang-8.
5. Architectures are auto-detected. Use make ARCH=i386 to force a build for i386. Other supported architectures are i486, i586, and i686. GCC 4.8 is the minimum requirement for correct codegen on older 32-bit architectures.

PowerPC support for openlibm was graciously sponsored by IBM.