set_except_vector question

[Lars Munch <lars@segv.dk>]

Hi

I have been looking at the set_except_vector function in
arch/mips[64]/kernel/traps.c and wondering why the handler
address is changed/recalculated before it is stored:

*(volatile u32 *)(KSEG0+0x200) = 0x08000000 | (0x03ffffff & (handler >> 2));
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  

Could someone please enlighten me?

Thanks
Lars Munch