lkml.org 
[lkml]   [1999]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [patch] string.h speedup, cld-2.3.30-A1
    From
    Date
    Henrik Olsen <henrik@iaeste.dk> writes:

    |> On Sat, 27 Nov 1999, Linus Torvalds wrote:
    |> > On Sat, 27 Nov 1999, Oliver Xymoron wrote:
    |> > > On Sat, 27 Nov 1999, Ingo Molnar wrote:
    |> > >
    |> > > > much of the remaining 284 cld's is still unjustified, because '*a = *b;'
    |> > > > type of structure copies are inlined by GCC. (GCC generates a cld because
    |> > > > user-space has to be prepared to be interrupted by uncooperative signal
    |> > > > handlers and the like).
    |> > >
    |> > > What!? A signal handler can change flags? Then there's a lot more for GCC
    |> > > to worry about than the direction flag..
    |> >
    |> > A normal signal handler cannot change flags, because they will obviously
    |> > be restored on signal exit.
    |> >
    |> > However, I'm not sure that "longjmp()" does the same. You'd have to check
    |> > libc souces to see if setjmp saves the flags..
    |> >
    |> > Linus
    |> Libc longjmp() does, glibc longjmp() doesn't.

    The flags are considered call clobbered, so setjmp does not save them.

    --
    Andreas Schwab "And now for something
    SuSE Labs completely different."
    schwab@suse.de
    SuSE GmbH, Schanzäckerstr. 10, D-90443 Nürnberg

    -
    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/

    \
     
     \ /
      Last update: 2005-03-22 13:55    [W:0.025 / U:1.656 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site