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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