fixed_point

The fixed_point library provides a header-only C++11 API for approximating real numbers using binary fixed-point arithmetic. It forms the reference implementation of a standard library proposal presented in paper, P0037 and is developed as part of study groups, SG14 and SG6.

Installation

The library is hosted on GitHub:

$ git clone https://github.com/johnmcfarlane/fixed_point.git

The API is exposed through headers in the include directory. Add this to your system header list and include, e.g.:

#include <sg14/fixed_point.h>

Tests and Benchmarks

Linux

Tested on Travis (Ubuntu 12.04) using GCC 4.8 and Clang 3.5 and Debian GNU/Linux 8.3 using GCC 4.9.2 and Clang 3.5.0.

Requires:

• GCC 4.8.4
• CMake 2.8.11

Optional:

• Boost - facilitates multiprecision support
• Doxygen - generates documentation in the doc/gh-pages directory
• cmark - generates proposal papers

For a list of configuration options:

$ cmake -LH

To build everything:

$ cmake -DCMAKE_BUILD_TYPE=Release
$ make

To disable exception handling, add -DEXCEPTIONS=OFF to the cmake command:

$ cmake -DCMAKE_BUILD_TYPE=Release -DEXCEPTIONS=OFF
$ make

To run tests:

$ cmake -DCMAKE_BUILD_TYPE=Release
$ make fp_test
$ ./fp_test

To run benchmarks:

$ cmake -DCMAKE_BUILD_TYPE=Release
$ make fp_benchmark
$ ./fp_benchmark

To profile benchmarks:

1. Build with frame pointers included:

   $ cmake -DCMAKE_BUILD_TYPE=Release -DPROFILE=ON
   $ make fp_benchmark
   $ ./fp_benchmark

2. then run:

   $ perf record -g ./fp_benchmark
   $ perf report -g 'graph,0.5,caller'

Windows

Tested on AppVeyor and on Windows 7 Professional with CMake 3.4.0. Requires:

• MSBuild 14.0
• CMake 2.8.11

To build vs/Release/fp_test.exe and vs/Release/fp_benchmark.exe:

cmake .
MSBuild.exe /m fixed_point.sln /p:Configuration=Release

For 64-bit builds, append Win64 to the -G option above:

cmake -G "Visual Studio 14 2015 Win64" .

Note that fp_benchmark is unlikely to produce valid results due to missing escape and clobber functions.

Cleaning

To clean the project files:

git clean -Xdff .

(Use with caution!)

Further Reading

• documentation
• latest draft of C++ Standard Library proposal, P0037 (revision 1, revision 0)
• position paper illustrating the elastic numeric type
• forum of Study Group 14

Contact Information

All feedback greatly appreciated.

• GitHub
• SG14 forum
• fixed-point@john.mcfarlane.name