LUI - RISC-V instruction reference

luiLoad upper immediate 
Sets t1 to a 20-bit immediate followed by 12 zero bits.
RISC-V manual: lui 
Forms  lui ,   
Pseudo-instructionsThe assembler turns these into one or more real instructions.
  lui , %hi()  
Set t1 to upper 20-bit label's address
Operands t1 Any integer register, x0 to x31, or its named alias, such as zero, t0 or t6. 
imm20 A 20-bit immediate, 0 to 1048575 (0xFFFFF), placed in bits 31–12. 
label A named address in the program, such as the start of a loop or a variable in .data. 
 # lui writes 73728 to t0.
.data
marker: .word 17
.text
lui t0, 18