AHB协议用systemverilog写driver实现二级流水的代码怎么写

以下是一份参考代码，实现了AHB协议的二级流水：

module ahb_driver(input wire HCLK, input wire HRESETn, input wire [31:0] HRDATA, output wire [31:0] HWDATA, input wire HSEL, input wire HTRANS, input wire HADDR, input wire [2:0] HSIZE, input wire [1:0] HBURST);

//定义二级流水需要的寄存器
reg [31:0] reg1_HRDATA;
reg [31:0] reg2_HRDATA;
reg [31:0] reg2_HWDATA;
reg [31:0] reg1_HADDR;
reg [31:0] reg2_HADDR;
reg [2:0] reg1_HSIZE;
reg [2:0] reg2_HSIZE;
reg [1:0] reg1_HBURST;
reg [1:0] reg2_HBURST;
reg reg1_valid;
reg reg2_valid;

//使用state机实现二级流水
enum states {IDLE, RD_REG1, RD_REG2, WR_REG2};
reg [2:0] state = IDLE;

//定义AHB协议的各种信号
wire [31:0] HRDATA_R;
wire [31:0] HWDATA_W;
wire HREADY_R, HREADY_W;
wire HRESP_R, HRESP_W;
assign HRDATA_R = (state == RD_REG1)? reg1_HRDATA : reg2_HRDATA;
assign HRESP_R = (state == RD_REG1)? 2'b10 : 2'b00; //2'b10表示OKAY，2'b00表示自增错误

//定义AHB协议的decoder
wire [31:0] HADDR_REG1 = {HADDR[31:3], 3'b000};
assign HREADY_R = (state == RD_REG1)? 1'b1 : 1'b0;
assign HREADY_W = (state == WR_REG2)? 1'b1 : 1'b0;

//规定AHB协议中的寄存器输出
ahb_slave dut(
    .HCLK(HCLK),
    .HRESETn(HRESETn),
    .HRDATA(HRDATA_R),
    .HREADY(HREADY_R),
    .HRESP(HRESP_R),
    .HWDATA(HWDATA_W),
    .HADDR((state == IDLE)? HADDR : ((state == RD_REG1)? HADDR_REG1 : reg2_HADDR)),
    .HSIZE((state == IDLE)? HSIZE : ((state == RD_REG1)? reg1_HSIZE : reg2_HSIZE)),
    .HBURST((state == IDLE)? HBURST : ((state == RD_REG1)? reg1_HBURST : reg2_HBURST)),
    .HMASTER(3'b000) //3'b000表示AHB总线上的Slave ID
);

//状态机实例
always @(posedge HCLK) begin
    if (HRESETn == 0) begin //复位状态
        state <= IDLE;
        reg1_valid <= 0;
        reg2_valid <= 0;
    end else begin
        case(state)
            IDLE: begin //等待HSEL
                if (HSEL) begin
                    reg1_HADDR <= HADDR;
                    reg1_HSIZE <= HSIZE;
                    reg1_HBURST <= HBURST;
                    reg1_HRDATA <= HRDATA;
                    reg1_valid <= 1;
                    state <= RD_REG1;
                end
            end
            RD_REG1: begin //第一级读取
                if (HREADY_R) begin
                    reg2_HADDR <= HADDR + HRDATA_R;
                    reg2_HSIZE <= reg1_HSIZE-1;
                    reg2_HBURST <= reg1_HBURST;
                    reg2_valid <= 1;
                    state <= RD_REG2;
                end
            end
            RD_REG2: begin //第二级读取
                if (HREADY_R) begin
                    reg2_HRDATA <= HRDATA_R;
                    state <= IDLE;
                end
            end
            WR_REG2: begin //第二级写入
                if (HREADY_W) begin
                    reg2_valid <= 0;
                    state <= IDLE;
                end
            end
        endcase
    end
end

endmodule

该代码使用了一个状态机，实现AHB协议中的二级流水。输入信号包括HCLK、HRESETn、HRDATA、HSEL、HTRANS、HADDR、HSIZE、HBURST，输出信号包括HREADY、HRESP、HWDATA。其中，HADDR、HSIZE、HBURST为输入信号，其他信号均为输出信号。