Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: Atomic operations | Date | 3 Jun 2002 11:43:07 -0700 |
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Followup to: <EE83E551E08D1D43AD52D50B9F5110927E7A15@ntserver2> By author: Gregory Giguashvili <Gregoryg@ParadigmGeo.com> In newsgroup: linux.dev.kernel > > Could you, please, clarify what you meant saying that there was no way of > doing so. I admit, I'm no expert in i386 assembly, but this operation seems > so simple to me... >
That doesn't mean the hardware is going to provide it atomically.
> > Could you, please, suggest some other implementation (with waiting and > trying again - whatever this means)? >
Very simple:
- Set a spinlock (note: you need a spinlock variable) - Read - Add - Clear spinlock
This is called "bootstrapping" -- using a more primitive atomic operation to get what you need.
-hpa -- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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