Messages in this thread | | | Date | Tue, 11 Mar 2008 07:43:25 +0100 | From | "H. Peter Anvin" <> | Subject | Re: P6 NOPs again: MPSC? |
| |
Hugh Dickins wrote: > > Yup, I realized that (with || in place of &&): I meant that perhaps > it was supposed to say X86_64 || (!X86_GENERIC && (M686 || ....)) > since quite a lot of other options there have "|| X86_64" to cover > all the 64-bit possibilities at once i.e. is it only MPSC that > needs to be added, or both MPSC and CPU_GENERIC? >
No. The left-hand clause (X86_64 || !X86_GENERIC) indicates when using these NOPs are *permitted*; the right-hand clause indicates when doing so is *desirable*. The latter isn't, for example, for K8, even on 64 bits.
-hpa
| |