请用verilog实现一个31个输入五位输出的华莱士树加法器，并给出它的testbench代码

下面是一个简单的Verilog代码示例，实现了一个31个输入五位输出的华莱士树加法器，包括一个顶层模块和两个子模块。

顶层模块：

module top_module(
    input [30:0] A,
    input [30:0] B,
    input [30:0] C,
    output reg [4:0] S
);

wire [4:0] s1, s2;
wire [30:0] c1, c2;

// 实例化两个子模块
adder5 #(31) adder1(.A(A), .B(B), .C(C), .S(s1), .Cout(c1));
adder5 #(31) adder2(.A(s1), .B("00000"), .C(c1), .S(s2), .Cout(c2));

// 输出结果
assign S = s2;

endmodule

子模块：

module adder5(
    input [4:0] A,
    input [4:0] B,
    input [4:0] C,
    output reg [4:0] S,
    output reg Cout
);

reg [4:0] temp1, temp2, temp3;
reg [5:0] carry;

always @(A or B or C) begin
    // 计算第一层
    for (int i=0; i<5; i=i+1) begin
        temp1[i] = A[i] ^ B[i] ^ C[i];
        carry[i+1] = (A[i] & B[i]) | (A[i] & C[i]) | (B[i] & C[i]);
    end

    // 计算第二层
    for (int i=0; i<4; i=i+1) begin
        temp2[i] = temp1[i] ^ temp1[i+1] ^ carry[i+1];
        carry[i+2] = (temp1[i] & temp1[i+1]) | (temp1[i] & carry[i+1]) | (temp1[i+1] & carry[i+1]);
    end

    // 计算第三层
    for (int i=0; i<3; i=i+1) begin
        temp3[i] = temp2[i] ^ temp2[i+1] ^ carry[i+2];
        carry[i+3] = (temp2[i] & temp2[i+1]) | (temp2[i] & carry[i+2]) | (temp2[i+1] & carry[i+2]);
    end

    // 计算第四层
    S[0] = temp3[0] ^ temp3[1] ^ carry[3];
    S[1] = temp3[1] ^ temp3[2] ^ carry[4];
    S[2] = temp3[2] ^ temp2[3] ^ carry[5];
    S[3] = temp2[3] ^ temp1[4] ^ carry[6];
    S[4] = temp1[4] ^ C[4] ^ carry[7];

    // 计算进位
    Cout = carry[7];
endmodule

testbench代码：

module top_module_tb();
reg [30:0] A, B, C;
wire [4:0] S;

top_module dut(.A(A), .B(B), .C(C), .S(S));

initial begin
    $dumpfile("dump.vcd");
    $dumpvars(0, top_module_tb);

    A = 'b000000000000000000000000000001;
    B = 'b000000000000000000000000000010;
    C = 'b000000000000000000000000000100;

    #10 $display("S = %b", S);

    A = 'b000000000000000000000000000110;
    B = 'b000000000000000000000000000111;
    C = 'b000000000000000000000000001000;

    #10 $display("S = %b", S);

    A = 'b000000000000000000000000001010;
    B = 'b000000000000000000000000001011;
    C = 'b000000000000000000000000001100;

    #10 $display("S = %b", S);

    // add more test cases...

    $finish;
end

endmodule

注意，这只是一个简单的实现示例，它可能需要根据具体需求进行优化。同时，测试用例也需要根据具体情况进行编写。