| commit | ab7671494a7f7f5ccdd0fa541a184088e34db43b | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Sat Feb 24 02:20:24 2024 +0000 |
| committer | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Sat Feb 24 02:20:24 2024 +0000 |
| tree | 726fe230524fb1ddb9efdd65d7dda0910035f996 | |
| parent | a555e78cea9d472dc5c3dfe6a1cb2f0979d93864 [diff] | |
| parent | acbb172367cb377f04686a2a8f8a9a2c894b2f7e [diff] |
Snap for 11492556 from acbb172367cb377f04686a2a8f8a9a2c894b2f7e to 24D1-release Change-Id: Ia2f299ca06d9c9e7c9995d7faaece0c3c83f7c81
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