Messages in this thread | | | Date | Tue, 15 Dec 1998 11:47:01 +0000 (GMT) | From | Tigran Aivazian <> | Subject | Re: 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.
Regards, Tigran.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |