commit | bcc6a5cbcd106b9e7371b0e4fb9103723f86645f | [log] [tgz] |
---|---|---|
author | Xin Li <delphij@google.com> | Sat Feb 20 14:10:24 2021 +0000 |
committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Sat Feb 20 14:10:24 2021 +0000 |
tree | 9e71b2fb2df83e4bfd8abbc2bfa56c2a09d0118e | |
parent | 62aa22257fc0a343e76f3dfd340555c32ee859a3 [diff] | |
parent | 908fa57b9943d8c70dab270ec7f1ec970a42dff0 [diff] |
[automerger skipped] Mark ab/7061308 as merged in stage. am: 757c347bd9 -s ours am: 9e8ff3c207 -s ours am: 908fa57b99 -s ours am skip reason: Change-Id I4950cd5b3b71e771b0766c9a1aba3657318c9127 with SHA-1 4a39f58be5 is in history Original change: undetermined MUST ONLY BE SUBMITTED BY AUTOMERGER Change-Id: Iff19166910b4d1b30573c3f939cfad135bce0da9
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); } }
Currently working features:
Platform | uint32_t | uint64_t | size_t |
---|---|---|---|
x86-64 gcc | Works | Works | Works |
x86-64 clang | Works | Works | Works |
x86-64 MSVC | Works | Works | Works |
x86 gcc | Works | Works | Works |
x86 clang | Works | Works | Works |
x86 MSVC | Works | Works | Works |
ARMv7 gcc | Works | Works | Works |
ARMv7 clang | Works | Works | Works |
ARMv7 MSVC* | Compiles | Compiles | Compiles |
ARM64 gcc | Works | Works | Works |
ARM64 clang | Works | Works | Works |
ARM64 MSVC* | Compiles | Compiles | Compiles |
PPC64 gcc | Works | Works | Works |
WAsm clang | Works | Works | Works |
Asm.js clang | Works | Works | Works |
PNaCl clang | Works | Works | Works |
CUDA | Untested | Untested | Untested |
OpenCL | Untested | Untested | Untested |
*ARMv7 and ARM64 builds with MSVC are presumed to work, but were only verified to compile successfully