Detail andi

.text
.equ SWITCHES, 0x0850
.global main
main:
movia r10,SWITCHES
ldwio r9,0(r10)
andi r9,r9,0xff# only receive 1 value: SWITCHES
ldwio r8,0(r10)
andi r8,r8,0x02# receive two value: 2 or SWITCHES value
br main
.end

I don't know why r9 receive only 1 value!

I formulation by JNIOSEmu

Thanks you