On Tue, Jun 13, 2006 at 12:01:39PM +0100, Andrew Haley wrote:
>
> All you've got here is an inline asm version of
>
> inline void longcpy(long* _dst, long* _src, unsigned _numwords)
> {
> __builtin_memcpy (_dst, _src, _numwords * sizeof (long));
> }
>
> which gcc will optimize if it can.
>
> These days, "rep movs" is not as advantageous as it once was, and you
> may get better performance by allowing gcc to choose how to do memory
> copies.
>
Hi Andrew,
Actually, I knew this, but I was using longcpy as a bellwether
of many more complex inline-asm functions in a c++ big integer
library.
I've just finished a trawl through the entire library, fixing a Good
Many Things which I now know (thanks to you guys) could really confuse
the optimiser.
Many thanks,
Andrew Walrond
