commit | eec669e2ac77932b889c5f3c525a9b553cab0141 | [log] [tgz] |
---|---|---|
author | Bob Badour <bbadour@google.com> | Thu Mar 26 01:18:20 2020 +0000 |
committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Thu Mar 26 01:18:20 2020 +0000 |
tree | 0ef1dc1b680fcb94028e5fa274c41efab1b40cc1 | |
parent | 5023fc0059e32629a4a79a50806cbe38d0d30487 [diff] | |
parent | 567aeded00ecf239b2ac3154e76cd585b86cf760 [diff] |
Remove redundant NOTICE symbolic link. am: 76a395c804 am: 31e86329bc am: 567aeded00 Change-Id: Ibf58562ea14abd949d49c082e98974f252ce20b7
Header-only library for division via fixed-point multiplication by inverse
On modern CPUs and GPUs integer division is several times slower than multiplication. FXdiv implements an algorithm to replace an integer division with a multiplication and two shifts. This algorithm improves performance when an application performs repeated divisions by the same divisor.
uint32_t
, uint64_t
, and size_t
#include <fxdiv.h> /* Division of array by a constant: reference implementation */ void divide_array_c(size_t length, uint32_t array[], uint32_t divisor) { for (size_t i = 0; i < length; i++) { array[i] /= divisor; } } /* Division of array by a constant: implementation with FXdiv */ void divide_array_fxdiv(size_t length, uint32_t array[], uint32_t divisor) { const struct fxdiv_divisor_uint32_t precomputed_divisor = fxdiv_init_uint32_t(divisor); for (size_t i = 0; i < length; i++) { array[i] = fxdiv_quotient_uint32_t(array[i], precomputed_divisor); } }
Project is in alpha stage. API is unstable. Currently working features:
Platform | uint32_t | uint64_t | size_t |
---|---|---|---|
x86-64 gcc | Works | Works | Works |
x86-64 MSVC | Works | Works | Works |
x86 gcc | Works | Works | Works |
x86 MSVC | Works | Works | Works |
ARMv7 gcc | Works | Works | Works |
PPC64 gcc | Works | Works | Works |
PNaCl clang | Works | Works | Works |
Asm.js clang | Works | Works | Works |
CUDA | Untested | Untested | Untested |
OpenCL | Untested | Untested | Untested |