On 02/03/2016 04:13 PM, Mikael Vidstedt wrote: > > On 2016-02-03 01:43, Andrew Haley wrote: >> On 02/02/16 19:25, 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. >> There doesn't seem to be any way to use a byte-swap instruction >> in the swapping code. This will make it unnecessarily slow. > > To be clear, this isn't trying to provide the absolutely most optimal > copy+swap implementation. It's trying to fix the Bits.c unaligned bug > and pave the way for further improvements. Further performance > improvements here are certainly possible, but at this point I'm happy as > long as the performance is on par (or better) with the Bits.c > implementation it's replacing.
Got it, sure. It's just nice to be able to replace low-level routines with platform ones. > That said, at least gcc seems to recognize the byte swapping pattern and > does emit a bswap on linux-x64. I'm not sure about the other platforms > though. Oh, very nice. Right, I'll check that once your patch does in. Andrew.
