tag | c81995ede750950e79c89ff06791818cbd563f5b | |
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tagger | The Android Open Source Project <initial-contribution@android.com> | Wed Apr 13 22:00:47 2022 -0700 |
object | 5e639ad18ba004dac1deb14541f6043d016f5ec4 |
Android Mainline 12.0.0 Release 60 (8075116,com.google.android.cellbroadcast)
commit | 5e639ad18ba004dac1deb14541f6043d016f5ec4 | [log] [tgz] |
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author | android-build-team Robot <android-build-team-robot@google.com> | Mon Jun 21 14:49:57 2021 +0000 |
committer | android-build-team Robot <android-build-team-robot@google.com> | Mon Jun 21 14:49:57 2021 +0000 |
tree | 9e71b2fb2df83e4bfd8abbc2bfa56c2a09d0118e | |
parent | c577b94ed81e89bb905b7cbba8043480561afda6 [diff] | |
parent | 98e601dca4378a805a0f4f2f4aa31c5f382749c0 [diff] |
Snap for 7478067 from 98e601dca4378a805a0f4f2f4aa31c5f382749c0 to mainline-cellbroadcast-release Change-Id: I2c63d593922948fe879069dc9994b995453d55fa
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