[lkml]   [1998]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: NOP instruction

On Tue, 15 Dec 1998, Gabriel Paubert wrote:
> Actually the Intel nop is coded as xchg [e]ax,[e]ax since the 8088. On the
> 386, it took exactly the same time as xchg [e]ax with any other register
> and was slow. From the 486 or Pentium, I can't remember, the NOP is
> optimized and much faster than the actual xchg instructions.
Besides xchg is atomic (which is why it is used in locking primitives (at least
on some systems)) and is to be avoided whenever possible.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:46    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean