linux setup

[zhaobin xv]

Hi
I recently read lernel source .
I have a question:In
folder:linux/arch/arm/boot/compressed/head.S(linux2.6.22.6):


start:
        .type    start,#function
        .rept    8
        mov    r0, r0
        .endr

        b    1f
        .word    0x016f2818        @ Magic numbers to help the loader
        .word    start            @ absolute load/run zImage address
        .word    _edata            @ zImage end address
1:        mov    r7, r1            @ save architecture ID
        mov    r8, r2            @ save atags pointer


I don't kown why the “mov r0 r0 ” repeated  emergence 8 times.