HDLBits Mux256to1v

题目如下要创建一个256选1的多路选择器

Create a 4-bit wide, 256-to-1 multiplexer. The 256 4-bit inputs are
all packed into a single 1024-bit input vector. sel=0 should select
bits in[3:0], sel=1 selects bits in[7:4], sel=2 selects bits in[11:8],
etc.

module top_module( 
    input [1023:0] in,
    input [7:0] sel,
    output [3:0] out );

思路
一开始是很容易想到要如下操作的