lkml.org 
[lkml]   [2009]   [Jul]   [3]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH -tip] x86: atomic64: inline atomic64_read()
FromAndi Kleen <>
DateFri, 03 Jul 2009 20:24:22 +0200
Arjan van de Ven <arjan@infradead.org> writes:

> On Fri, 3 Jul 2009 20:04:50 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
>
>> > +static inline u64 atomic64_read(atomic64_t *ptr)
>> > +{
>> > + u64 res;
>> > +
>> > + asm volatile(
>> > + "mov %%ebx, %%eax\n\t"
>> > + "mov %%ecx, %%edx\n\t"
>> > + LOCK_PREFIX "cmpxchg8b %1\n"
>
> also afaik cmpxchg implies the lock prefix, so no need to make an
> explicit one... it just adds code size and alternatives-work

No it doesn't; LOCK is implied for "xchg", but not for cmpxchg

-Andi

--
ak@linux.intel.com -- Speaking for myself only.


\
 
 \ /
  Last update: 2009-07-03 20:27    [from the cache]
©2003-2009