libsimdpp is a portable header-only zero-overhead C++ low level SIMD library. The library presents a single interface over SIMD instruction sets present in x86, ARM, PowerPC and MIPS architectures. On architectures that support different SIMD instruction sets the library allows the same source code files to be compiled for each SIMD instruction set and then hooked into an internal or third-party dynamic dispatch mechanism. This allows the capabilities of the processor to be queried on runtime and the most efficient implementation to be selected. The library sits somewhere in the middle between programming directly in SIMD intrinsics and even higher-level SIMD libraries. As much control as possible is given to the developer, so that it's possible to exactly predict what code the compiler will generate.