Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 1 Oct 2014 11:44:44 -0700 | Subject | Re: [PATCH v3 2/2] x86_64: Don't save flags on context switch |
| |
On Wed, Oct 1, 2014 at 11:35 AM, H. Peter Anvin <hpa@zytor.com> wrote: > On 10/01/2014 11:28 AM, Andy Lutomirski wrote: >> >> #define __EXTRA_CLOBBER \ >> , "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \ >> - "r12", "r13", "r14", "r15" >> + "r12", "r13", "r14", "r15", "flags" >> > > I was under the impression that gcc *always* assumes the flags were > clobbered for an asm statement. Otherwise I think we'd have a lot of > problems. >
I have no idea, but I doubt that adding the explicit "flags" clobber hurts, and it will make other people who are unsure about this less worried.
--Andy
> -hpa > >
-- Andy Lutomirski AMA Capital Management, LLC
| |