RISC-V: Implementing SLLI, SRLI and SRAI

You can find the answer directly in the RISC-V specifications.

Encoding of SARI, SLLI and SRLI

 imm[11:5]    imm[4:0]   rs1    func3   rd   opcode    inst
------------------------------------------------------------
 0000000      shamt      rs1    001     rd   0010011   SLLI
 0000000      shamt      rs1    101     rd   0010011   SRLI
 0100000      shamt      rs1    101     rd   0010011   SRAI

As for the latency, the ISA only deals with architectures not micro-architectures.
That means that two RISC-V conforming CPUs can execute a shift in a different number of clock cycles.