tag | ed1b9fa519bb402a5148e3625419610679ebe7a2 | |
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tagger | The Android Open Source Project <initial-contribution@android.com> | Mon Oct 05 15:24:35 2020 -0700 |
object | e3d3a2eb281293de6b2f590899ef7df25a1e2226 |
Android 11.0.0 Release 6 (RPM1.200923.001)
commit | e3d3a2eb281293de6b2f590899ef7df25a1e2226 | [log] [tgz] |
---|---|---|
author | android-build-team Robot <android-build-team-robot@google.com> | Thu Feb 13 04:26:45 2020 +0000 |
committer | android-build-team Robot <android-build-team-robot@google.com> | Thu Feb 13 04:26:45 2020 +0000 |
tree | 7e85e45ccb22a7b95f1dd9df988edec9e6396799 | |
parent | 33a70410818d3156235081a932b85a1f8d821cfb [diff] | |
parent | c577b94ed81e89bb905b7cbba8043480561afda6 [diff] |
Snap for 6203617 from c577b94ed81e89bb905b7cbba8043480561afda6 to rvc-release Change-Id: I8ad2f2647e48cb06dd2e69cc085c72dfdba91e38
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 |