题解 | #位拆分与运算#sel＝0才输入有效

`timescale 1ns/1ns

module data_cal(
input clk,
input rst,
input [15:0]d,
input [1:0]sel,

output [4:0]out,
output validout
);
//*************code***********//
reg[4:0]        out;
reg             validout;
reg[15:0]       d_mid;

always@(posedge clk or negedge rst)begin
    if(~rst)begin
        out <= 0;validout <= 0;d_mid <= 0;
    end
    else if(sel == 0)begin
        d_mid <= d;
    end
end

always@(posedge clk or negedge rst)begin
        case(sel)
        0://
        begin
            out <= 0;
            validout <= 0;
        end
        1://
        begin
            out <= d_mid[3:0] + d_mid[7:4];
            validout <= 1;
        end
        2://
        begin
            out <= d_mid[3:0] + d_mid[11:8];
            validout <= 1;
        end
        3://
        begin
            out <= d_mid[3:0] + d_mid[15:12];
            validout <= 1;
        end
        endcase
end

//*************code***********//
endmodule