LUI - MIPS instruction reference

luiLoad upper immediate 
Puts a 16-bit immediate into the upper half of $t1 and clears the lower half, often as the first step of a 32-bit constant.
Forms  lui ,   
Pseudo-instructionsThe assembler turns these into one or more real instructions.
  lui , %hi()  
Set $t1 to the upper 16 bits of label's address, adjusted so that a following %lo lands on the label. Pairs with an instruction taking %lo(label)($t1)
Operands $t1 Any general-purpose register, $0 to $31, using its numeric or named spelling, such as $8 or $t0 ($zero is $0; $ra is $31). 
uimm16 An unsigned 16-bit immediate, 0 to 65535. 
label A named address in the program, such as the start of a loop or a variable in .data. 
Used to build a full 32-bit constant: first 'lui $t1,upper16' then 'ori $t1,$t1,lower16'. Example: to load 0x12345678 use 'lui $t1,0x1234' then 'ori $t1,$t1,0x5678'.
 # Place 0x1234 in the upper half of $t0. Inspect $t0: 0x12340000.
lui $t0, 0x1234