Re: what's the meaning of "%%fs" ?

%fs is a segment register. More details, see http://en.wikipedia.org/wiki/X86_assembly_language , section "Registers", "Segmented addressing". On Thu, May 9, 2013 at 6:04 PM, lx <lxlenovostar@gmail.com> wrote:

hi all: the codes is:

extern inline unsigned char get_fs_byte(const char * addr) { unsigned register char _v;

__asm__ ("movb %%fs:%1,%0":"=r" (_v):"m" (*addr)); return _v; }

What's the meaning of "%%fs" ?

Is " __asm__ ("movb %1,%0":"=r" (_v):"m" (*addr));" not ok?

Thank you.

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