About

This example demonstrates how to :

• generate a library containing a procedure written in ARMv7 GNU ASsembly
• call this procedure from a Android app using the JNI
• call a Java method, defined in the Android app, from the Assembly procedure using the JNI

Building

Building using GNU Make

Requirements

• GNU AS
• Gold linker
• 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="armv7a-hardfloat-linux-gnueabi"
export APP_DIR="./apk"
export LIBNAME="libarcane.so"
$PREFIX-as -o decypherArcane.o decypherArcane.s
$PREFIX-ld.gold -shared --dynamic-linker=/system/bin/linker -shared --hash-style=sysv -o $LIBNAME decypherArcane.o
mkdir -p $APP_DIR/app/src/main/jniLibs/armeabi{,-v7a}
cp $LIBNAME $APP_DIR/app/src/main/jniLibs/armeabi
cp $LIBNAME $APP_DIR/app/src/main/jniLibs/armeabi-v7a

Building using Android ndk-build

Requirements

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

Build

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

Installing the prepared APK

• Connect your ARMv7 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