Updated documentation

* Fixed an error caused by a newline missing in line 187
* Added section about building natively on Windows on ARM
* Resolves MLCE-739

Change-Id: I2f452d77247b2a264e7f122d97cbb8f288716971
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/7992
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>

1 files changed, 36 insertions, 3 deletions

diff --git a/docs/user_guide/how_to_build_and_run_examples.dox b/docs/user_guide/how_to_build_and_run_examples.dox
index e48b2b74eb..077baf9d47 100644
--- a/docs/user_guide/how_to_build_and_run_examples.dox
+++ b/docs/user_guide/how_to_build_and_run_examples.dox
@@ -184,6 +184,7 @@ For NDK r18 or older, here is a guide to <a href="https://developer.android.com/
 	$NDK/build/tools/make_standalone_toolchain.py --arch arm --install-dir $MY_TOOLCHAINS/arm-linux-android-ndk-r18b --stl libc++ --api 21
 
 For NDK r19 or newer, you can directly <a href="https://developer.android.com/ndk/downloads">Download</a> the NDK package for your development platform, without the need to launch the make_standalone_toolchain.py script. You can find all the prebuilt binaries inside $NDK/toolchains/llvm/prebuilt/$OS_ARCH/bin/.
+
 @parblock
 @attention The building script will look for a binary named "aarch64-linux-android-clang++", while the prebuilt binaries will have their API version as a suffix to their filename (e.g. "aarch64-linux-android21-clang++"). You can instruct scons to use the correct version by using a combination of the toolchain_prefix and the "CC" "CXX" environment variables.
 @attention For this particular example, you can specify:
@@ -309,14 +310,14 @@ To cross-compile the library with Arm® Neon™ support for baremetal armv8a:
 
 Examples are disabled when building for bare metal. If you want to build the examples you need to provide a custom bootcode depending on the target architecture and link against the compute library. More information about bare metal bootcode can be found <a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dai0527a/index.html">here</a>.
 
-@section S1_6_windows_host Building on a Windows host system
+@section S1_6_windows_host Building on a Windows host system (cross-compile)
 
 Using `scons` directly from the Windows command line is known to cause
 problems. The reason seems to be that if `scons` is setup for cross-compilation
 it gets confused about Windows style paths (using backslashes). Thus it is
 recommended to follow one of the options outlined below.
 
-@subsection S1_6_1_ubuntu_on_windows Bash on Ubuntu on Windows
+@subsection S1_6_1_ubuntu_on_windows Bash on Ubuntu on Windows (cross-compile)
 
 The best and easiest option is to use
 <a href="https://msdn.microsoft.com/en-gb/commandline/wsl/about">Ubuntu on Windows</a>.
@@ -324,7 +325,7 @@ This feature is still marked as *beta* and thus might not be available.
 However, if it is building the library is as simple as opening a *Bash on
 Ubuntu on Windows* shell and following the general guidelines given above.
 
-@subsection S1_6_2_cygwin Cygwin
+@subsection S1_6_2_cygwin Cygwin (cross-compile)
 
 If the Windows subsystem for Linux is not available <a href="https://www.cygwin.com/">Cygwin</a>
 can be used to install and run `scons`, the minimum Cygwin version must be 3.0.7 or later. In addition
@@ -337,6 +338,38 @@ compiler is included in the Android standalone toolchain. After everything has
 been set up in the Cygwin terminal the general guide on building the library
 can be followed.
 
+@subsection S1_6_3_WoA Windows on ARM (native build)
+
+    Native builds on Windows are experimental and some features from the library interacting with the OS are missing.
+
+It's possible to build Compute Library natively on a windows system running on ARM.
+
+Windows on ARM(WoA) systems provide compatibility emulating x86 binaries on aarch64. Unfortunately Visual Studio 2022 does not work on aarch64 systems because it's an x86_64bit application and these binaries cannot be exectuted on WoA yet.
+
+Because we cannot use Visual Studio to build Compute Library we have to set up a native standalone toolchain to compile C++ code for arm64 on Windows.
+
+Native arm64 toolchain installation for WoA:
+- LLVM+Clang-12 which can be downloaded from: https://github.com/llvm/llvm-project/releases/download/llvmorg-12.0.0/LLVM-12.0.0-woa64.exe
+- Arm64 VC Runtime which can be downloaded from  https://aka.ms/vs/17/release/vc_redist.arm64.exe
+
+- While full VS22 cannot be installed on WoA, we can install some components
+    -# Desktop development with C++ and all Arm64 components for Visual Studio, refer to:  https://developer.arm.com/documentation/102528/0100/Install-Visual-Studio
+    -# VS22 build tools: https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2022
+
+There are some additional tools we need to install to build Compute Library:
+
+- git https://git-scm.com/download/win
+- python 3 https://www.python.org/downloads/windows/
+- scons can be installed with pip install scons
+
+In order to use clang to build windows binaries natively we have to initialize the environment variables from VS22 correctly so that the compiler could find the arm64 C++ libraries. This can be done by pressing the key windows + r  and running the command:
+
+    cmd /k "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\Build\vcvarsx86_arm64.bat"
+
+To build Compute Library type:
+
+     scons opencl=0 neon=1 os=windows examples=0 validation_tests=1 benchmark_examples=0 build=native arch=armv8a Werror=0 exceptions=1 standalone=1
+
 @section S1_7_cl_requirements OpenCL DDK Requirements
 
 @subsection S1_7_1_cl_hard_requirements Hard Requirements