| commit | 1726d0b9d9150555b49cb811fa0187fabf08d4e9 | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Tue Apr 30 23:07:28 2024 +0000 |
| committer | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Tue Apr 30 23:07:28 2024 +0000 |
| tree | 726fe230524fb1ddb9efdd65d7dda0910035f996 | |
| parent | b33d45d3a20c474c277a0bdaf77c3c913d09c496 [diff] | |
| parent | 46dbe23922d2f68acf6638846c68716fcec3e8fa [diff] |
Snap for 11784291 from 46dbe23922d2f68acf6638846c68716fcec3e8fa to 24Q3-release Change-Id: Ib3e7eb1fa3ffbc22a391dcff9476a5cda40628d8
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