On Sat, Jan 9, 2016 at 9:48 AM, Tony Luck <tony.luck(a)gmail.com> wrote:
On Fri, Jan 8, 2016 at 5:49 PM, Andy Lutomirski
> On Jan 8, 2016 4:19 PM, "Tony Luck" <tony.luck(a)intel.com> wrote:
>> Make use of the EXTABLE_FAULT exception table entries. This routine
>> returns a structure to indicate the result of the copy:
> Perhaps this is silly, but could we make this feature depend on ERMS
> and thus make the code a lot simpler?
It's the fast string extension, aka Enhanced REP MOV STOS. On CPUs
with that feature (and not disabled via MSR), plain ol' rep movs is
the fastest way to copy bytes. I think this includes all Intel CPUs
from SNB onwards.