Note that RISC-V can have 32, 64 or 128 bit wide registers. The instruction length can be any multiple of 16 bits, though the base instructions are all 32 bits

Note that RISC-V can have 32, 64 or 128 bit wide registers. The instruction length can be any multiple of 16 bits, though the base instructions are all 32 bits and the C extension adds 16 bit instructions and other lengths have not yet been used. This diagram shows how instructions up to 192 bits long can be encoded: https://www.embarcados.com.br/wp-content/uploads/2017/05/RISCV_length.jpg https://www.embarcados.com.br/wp-content/uploads/2017/05/RIS... It is a very simple circuit that can take the bottom 16 bits of any RISC-V instruction and tell you exactly how long it is, unlike the x86 where you need a sequence of steps.