BINVI - RISC-V instruction reference

binviInvert bit by immediate 
Sets t1 to t2 with the bit numbered by the immediate flipped.
RISC-V manual: binvi 
Forms  binvi , ,   
Operands t1 Any integer register, x0 to x31, or its named alias, such as zero, t0 or t6. 
t2 An integer register. It may be the same register as t1. 
imm6 An unsigned shift count or bit number: 0 to 63 in RV64, or 0 to 31 in RV32. 
 .text
li t0, 13
# t0=13, immediate 2; binvi writes 9 to t2.
binvi t2, t0, 2