题解 | #位拆分与运算#
位拆分与运算
https://www.nowcoder.com/practice/1649582a755a4fabb9763d07e62a9752
`timescale 1ns/1ns module data_cal( input clk, input rst, input [15:0]d, input [1:0]sel, // 注意添加reg,题目中说明了输出是reg类型 output reg [4:0]out, output reg validout ); //*************code***********// reg [15:0] din; always @(posedge clk or negedge rst) begin if (!rst) begin din <= 0; out <= 0; validout <= 0; end else begin case(sel) 0: begin din <= d; // 保存此时的输入 out <= 0; // sel为0时,输出重置为0 validout <= 0; end 1: begin out <= din[3:0] + din[7:4]; validout <= 1; end 2: begin out <= din[3:0] + din[11:8]; validout <= 1; end 3: begin out <= din[3:0] + din[15:12]; validout <= 1; end endcase end end //*************code***********// endmodule