移位运算hao

已知d为一个8位数，请在每个时钟周期分别输出该数乘1/3/7/8,并输出一个信号通知此时刻输入的d有效（d给出的信号的上升沿表示写入有效）

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

parameter flag_max = 2'd3;
reg[1:0] flag;
reg[10:0] out_reg;


always@(posedge clk or negedge rst) begin
    if(!rst) begin
        flag <= 2'b0;
    end
    else if(flag == flag_max) begin
        flag<= 2'b0;
    end
    else begin
        flag <= flag + 1'b1;
    end
end




always@(posedge clk or negedge rst)
begin
    if(!rst)begin
        input_grant <= 0;
        out <= 0;
    end
    else begin
        case(flag) 
            2'b0: begin
                input_grant <= 1'b1;
                out_reg <= d;
                out <= d;
            end
            2'd1: begin
                input_grant <= 1'b0;
                out <= out_reg *3;
            end
            2'd2: begin
                input_grant <= 1'b0;
                out <= out_reg *7;
            end
            2'd3: begin
                input_grant <= 1'b0;
                out <= out_reg *8;
            end
            default: begin
                out <= 10'd0;
                input_grant <=1'b0;
            end
        endcase
        end
end
//*************code***********//
endmodule