Unsafe.{get,put}-X-Unaligned; Efficient array comparison intrinsics

David Holmes david.holmes at oracle.com
Sun Mar 8 23:11:54 UTC 2015

On 7/03/2015 4:50 AM, Andrew Haley wrote:
> I've tried to so everything I've been asked.  If this version passes
> muster with everyone I'll Javadoc all the public methods and fields
> and put it up for RFA next week.
> I guess it's going to need a lot of testing and security analysis.
> I added versions of all {put,get} methods with the boolean bigEndian
> argument.  This makes HeapByteBuffer much cleaner, and it does not
> need to know the machine endianness at all.  I hope that's OK.
> Andrew.
> http://cr.openjdk.java.net/~aph/unaligned.hotspot.4/
> http://cr.openjdk.java.net/~aph/unaligned.jdk.4/

I think it is cleaner and more efficient if Unsafe maintains BE as an 
instance variable (initialized at construction) and that isBigEndian() 
simply returns that. The native check should only need to be called once 
in the lifetime of the VM.


More information about the hotspot-compiler-dev mailing list