RFR JDK-8141491: Unaligned memory access in Bits.c

[Andrew Haley]

On 02/02/2016 07:25 PM, Mikael Vidstedt wrote:
> Please review this change which introduces a Copy::conjoint_swap and an 
> Unsafe.copySwapMemory method to call it from Java, along with the 
> necessary changes to have java.nio.Bits call it instead of the Bits.c code.
> 
> http://cr.openjdk.java.net/~mikael/webrevs/8141491/webrev.03/hotspot/webrev/
> http://cr.openjdk.java.net/~mikael/webrevs/8141491/webrev.03/jdk/webrev/

One other little thing: why are the byte-swapping methods in class nio.Bits
not called copySwapSomething?  e.g.:

 826     /**
 827      * Copy and byte swap 16 bit elements from off-heap memory to a heap array
 828      *
 829      * @param srcAddr
 830      *        source address
 831      * @param dst
 832      *        destination array, must be a 16-bit primitive array type
 833      * @param dstPos
 834      *        byte offset within the destination array of the first element to write
 835      * @param length
 836      *        number of bytes to copy
 837      */
 838     static void copyToCharArray(long srcAddr, Object dst, long dstPos, long length) {
 839         unsafe.copySwapMemory(null, srcAddr, dst, unsafe.arrayBaseOffset(dst.getClass()) + dstPos, length, 2);
 840     }

Andrew.