What's the value of %cs before jump in pm32 on booting?

Hi all: on booting of x86 top of file arch/x86/boot/pmjump.S there is code ------------------- GLOBAL(protected_mode_jump) movl %edx, %esi xorl %ebx, %ebx movw %cs, %bx shll $4, %ebx addl %ebx, 2f ... ------------------- what's the value of %cs here? how was it loaded? i would really appreciate if someone provide me some references thank you very much 2011-08-11 jiangtao.jit