题解 | #移位运算与乘法#

`timescale 1ns/1ns
module multi_sel(
input [7:0]d ,
input clk,
input rst,
output reg input_grant,
output reg [10:0]out
);
//*************code***********//

reg [1:0] counter;
reg [7:0] d_reserved;

always @(posedge clk, negedge rst) begin
    if(!rst) 
        counter <= 0;
    else if(counter == 3)
        counter <= 0;
    else
        counter <= counter + 1;
end

always @(posedge clk, negedge rst) begin
    if(!rst) begin
        out = 0;
        input_grant = 0;
    end
    else begin
        case(counter)
            2'b00: 
                begin
                    d_reserved = d;
                    out = d_reserved * 1;
                    input_grant = 1;
                end
            2'b01: 
                begin
                    out = d_reserved * 3;
                    input_grant = 0;
                end
            2'b10: 
                begin
                    out = d_reserved * 7;
                    input_grant = 0;
                end
            2'b11: 
                begin
                    out = d_reserved * 8;
                    input_grant = 0;
                end
        endcase
    end
end

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