Messages in this thread | | | Date | Sun, 2 Mar 2003 19:25:43 +0100 (CET) | From | Roman Zippel <> | Subject | Re: [PATCH] Multiple & vs. && and | vs. || bugs in 2.4.20 |
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Hi,
On Sun, 2 Mar 2003, Ulrich Drepper wrote:
> > - if (!urb->status & !acm->throttle) { > > + if (!urb->status && !acm->throttle) { > > [...] > > Observe the extra 'jne' and the fact that the value of 'throttle' > element cannot be loaded until after the conditional jump. Not even > out of order execution can arrange that.
But speculative execution can arrange that (providing the cpu predicted the jump target correctly).
> To summarize, I'd probably not be amused if you would change any of my > code which takes advantage of such programming finess.
If that was really intentional, I would assume to see something like this:
if (!(urb->status | acm->throttle)) {
bye, Roman
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