Re: Question about missing "cld" in x86 string assembly code

[Linus Torvalds]

On Sat, Dec 17, 2011 at 9:08 AM, Brian Gerst <brgerst@xxxxxxxxx> wrote:
>
> The i386 ELF ABI states "The direction flag must be set to the
> ‘‘forward’’ (that is, zero) direction before entry and upon exit from
> a function."  Therefore it can be assumed to be clear, unless
> explicitly set.

The exception, of course, being bootup, fault and interrupt handlers,
and after we've called out to foreign code (ie BIOS).

So there *are* a few cld's sprinkled around, they are just fairly rare.

                    Linus
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