MTC0 - MIPS instruction reference

mtc0Move to coprocessor 0 
Writes the value of general-purpose register $t1 into a Coprocessor 0 (CP0) control register.
Used in Exceptions and coprocessor 0MIPS assembly
 
Forms  mtc0 ,   
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). 
$8 A coprocessor 0 register, written by number: $8 (vaddr), $12 (status), $13 (cause) or $14 (epc). 
Used by exception handlers to modify the Status and Cause registers or to clear the EPC.
 # Write 0x1234 to CP0 vaddr register 8. Inspect CP0 $8: 0x1234.
li $t0, 0x1234
mtc0 $t0, $8