Re: asm volatile

[Seth Arnold <sarnold@wirex.com>]

On Sun, Mar 16, 2003 at 01:52:52PM -0500, Po Ki Chui wrote:
> Hi, I just start to learn Linux kernel programming. Does any of you know
> what "asm volatile" or "__asm__ __volatile__" is? It seems like it is
> telling the compiler to convert the code into assembly code, but what
> does it exactly do? Here is an example:

The following quote is from "info gcc" -- which I strongly recommend
reading any time you can't figure out what some piece of kernel source
does. (Well, I _hate_ the info format, and the info reader more, but
emacs users might find it rather at home. And other people find pinfo
more reasonable.)

   You can prevent an `asm' instruction from being deleted, moved
   significantly, or combined, by writing the keyword `volatile' after
   the `asm'.  For example:

Cheers!

-- 
"It's just PR.  They repeat "small government" enough, and people start
to look past the facts." -- Matt B

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