SLLIW: RISC-V instruction reference

slliwShift left logical immediate word (32-bit) RV64 only
Shifts the low 32 bits of the second register left by an immediate amount and sign-extends the result into the first.
RISC-V manual: slliw 
Forms  slliw , ,   
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. 
imm5 An unsigned 5-bit immediate, 0 to 31, used for values such as a shift count or a CSR immediate. 
This example runs on RV64.
 .text
li t0, 13
# t0=13, immediate 2; slliw writes 52 to t2.
slliw t2, t0, 2