Overview
libsimdpp is a portable header-only zero-overhead C++ wrapper around single-instruction multiple-data (SIMD) intrinsics found in many compilers. The library presents a single interface over several instruction sets. In addition to that, the library allows to compile the same source code for different instruction sets and seamlessly hook the implementations to an internal dynamic dispatch mechanism.
The library resolves differences between instruction sets by implementing the missing functionality as a combination of several intrinsics. Moreover, the library supplies a lot of additional, commonly used functionality, such as various variants of matrix transpositions, interleaving loads/stores, optimized compile-time shuffling instructions, etc. Each of these are implemented in the most efficient manner for the target instruction set.
The library sits somewhere in the middle between programming directly in 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.
Compiler and instruction set support
- This describes the current branch only which may be unstable or otherwise unfit for use. For available releases please see the libsimdpp wiki.
The library supports the following architectures and instruction sets:
- x86, x86-64: SSE2, SSE3, SSSE3, SSE4.1, AVX, AVX2, FMA3, FMA4, AVX-512F, XOP
- ARM, ARM64: NEON
Code for ALTIVEC instruction set has been added, but it has not been tested on actual hardware, thus definitely contains bugs.
The primary development of the library happens in C++11. A C++98-compatible version of the library is provided on the cxx98 branch. Boost libraries are used as a replacement for C++11-only functionality. The library does not depend on boost if the built-in dispatcher functionality is not used. The following compilers are supported:
- C++11 version:
- GCC: 4.9, 4.8
- Clang: 3.3, 3.4, 3.5
- MSVC: 2013
- ICC: 2015, 2013
Clang 3.3 is not supported on ARM. MSVC is only supported on x86-64. ICC is only supported on x86 and x86-64.
- C++98 version
- GCC: 4.8.1, 4.7.3
- Clang: 3.3, 3.4
The C++98 version has been tested with boost 1.53 and 1.54. Most probably other versions will work too.
Documentation
Online documentation is provided here.
License
The library is distributed under the Boost Software License, Version 1.0
Boost Software License - Version 1.0 - August 17th, 2003
Permission is hereby granted, free of charge, to any person or organization obtaining a copy of the software and accompanying documentation covered by this license (the "Software") to use, reproduce, display, distribute, execute, and transmit the Software, and to prepare derivative works of the Software, and to permit third-parties to whom the Software is furnished to do so, all subject to the following:
The copyright notices in the Software and this entire statement, including the above license grant, this restriction and the following disclaimer, must be included in all copies of the Software, in whole or in part, and all derivative works of the Software, unless such copies or derivative works are solely in the form of machine-executable object code generated by a source language processor.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.