.definelabel USER_RAM,0xA0000000
foo equ 0x100 ;represents an offset from USER_RAM. Indexed offsetting can only be done at compile time in MIPS.

la $t0,USER_RAM
nop ;load delay slot ($t0 might not be ready by the time the load occurs)
lbu $t1,foo($t0)  ;load the unsigned byte from memory address 0xA0000100