i386 inline-asm string functions - some questions

Denis Zaitsev zzz@anda.ru
Mon Dec 29 19:38:00 GMT 2003


On Tue, Dec 30, 2003 at 12:31:47AM +0500, Denis Zaitsev wrote:

> On Mon, Dec 29, 2003 at 11:09:14AM -0800, Zack Weinberg wrote:

> > Same if the out-of-line memcpy takes several more instructions to
> > set up but makes damn sure to do aligned memory accesses
> > (full-bus-width loads, nontemporal store, prefetches, etc etc etc),
> > whereas the inline one doesn't.

Sorry, I mean the inline functions below!  Of course!

> First, they are trying to do so here and there (but ok, not fine).
> 
> Second, I have experimented with this nonaligned access some time
> ago.  I don't remember exactly, but it seems that the modern x86
> processors do the job as fine as when the memory access is aligned.
> But as it was too far ago, I can't recollect the details and so I
> won't insist.  Better I will repeat the measurements...



More information about the Libc-alpha mailing list