Why use armeabi-v7a code over armeabi code

Question

In my current project I make use of multiple  so files  These are located at the armeabi and armeabi-v7a folder  Unfortunately one of the  so files is a 6MB and I need to reduce file size  Instead of having a fat APK file  I would like to use just the armeabi files and remove the armeabi-v7a folder   According to the NDK documentation  armeabi-v7a code is extended armeabi code which can contain extra CPU instructions  This all goes beyond my expertise  but I question why one would like to have both armeabi-v7a and armeabi code  There must be a good reason to have both  right   On my test devices this all seem to work fine  These have ARM v7 CPU s  Is it safe to assume that everything works now

User · Answer

Instead of having a fat APK file  I would like to use just the armeabi files and remove the armeabi-v7a folder    The opposite is a much better strategy  If you have minSdkVersion to 14 and upload your apk to the play store  you ll notice you ll support the same number of devices whether you support armeabi or not  Therefore  there are no devices with Android 4 or higher which would benefit from armeabi at all   This is probably why the Android NDK doesn t even support armeabi anymore as per revision r17b   source

User · Answer

EABI   Embedded Application Binary Interface  It is such specifications to which an executable must conform in order to execute in a specific execution environment  It also specifies various aspects of compilation and linkage required for interoperation between toolchains used for the ARM Architecture  In this context when we speak about armeabi we speak about ARM architecture and GNU Linux OS  Android follows the little-endian ARM GNU Linux ABI   armeabi application will run on ARMv5  e g  ARM9  and ARMv6  e g  ARM11   You may use Floating Point hardware if you build your application using proper GCC options like -mfpu vfpv3 -mfloat-abi softfp which tells compiler to generate floating point instructions for VFP hardware and enables the soft-float calling conventions  armeabi doesn t support hard-float calling conventions  it means FP registers are not used to contain arguments for a function   but FP operations in HW are still supported   armeabi-v7a application will run on Cortex A  devices like Cortex A8  A9  and A15  It supports multi-core processors and it supports -mfloat-abi hard  So  if you build your application using -mfloat-abi hard  many of your function calls will be faster

User · Answer

Depends on what your native code does  but v7a has support for hardware floating point operations  which makes a huge difference  armeabi will work fine on all devices  but will be a lot slower  and won t take advantage of newer devices  CPU capabilities  Do take some benchmarks for your particular application  but removing the armeabi-v7a binaries is generally not a good idea  If  you need to reduce size  you might want to have two separate apks for older  armeabi  and newer  armeabi-v7a  devices

[android] Why use armeabi-v7a code over armeabi code?

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