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About

This example demonstrates how to :

• assemble a library written with the ARMv8-A 64 bits GNU ASsembly syntax
• call a native procedure, defined in this library, from a Android app using the JNI
• display the value returned by this native procedure in the Android app

Building

Building using GNU Make

Requirements

• GNU AS (aarch64)
• Gold linker (aarch64)
• An ARM Android phone/emulator on which you have installation privileges

Build

Run make from this folder

Manually

Run the following commands :

# cross compiler prefix. Remove if you're assembling from an ARM machine
export PREFIX="aarch64-linux-gnu-"
export DEST="./apk/app/src/main/jniLibs"
$PREFIX-as -o wild.o wild.s
$PREFIX-ld.gold -shared --dynamic-linker=/system/bin/linker -shared --hash-style=sysv -o libwildAssembly.so wild.o
mkdir -p $DEST/arm64-v8a
cp libwildAssembly.so $DEST/arm64-v8a/libwildAssembly.so

Building using Android ndk-build

Requirements

• The Android NDK path in your system's PATH directory

Build

Open a shell or a command window in this folder and :

• On Windows, run 'mkbuild'
• On Linux, run 'mkbuild.sh'

Installing the prepared APK

• Connect your ARMv8-A Android phone/emulator
• open a shell or a "command window"
• cd to the apk folder

Then :

• On Windows run gradlew installDebug.
• On Linux run ./gradlew installDebug

Install

Connect your ARMv7 Android phone/emulator and run ./gradlew installDebug from the apk folder.