请给出用verilog语言实现以下功能的代码:由按键KEY0、KEY1控制计数器的值并在数码管上显示,每按下抬起一次KEY0计数加1,每按下抬起一次KEY1计数减1,计数加到100时归零,按照十进制在数码管的两位上动态显示,先显示十位再显示个位，其中两个数码管共阴极，其它管脚接在一起实现段选复用，由位选选择控制两位数码管的动态显示，按下复位按钮后计数归零，并给出响应的检测其功能的testbentch测试文件代码

以下是用Verilog语言实现功能的代码：

module counter(
    input CLK, //时钟信号
    input RST, //复位信号
    input KEY0, //按键0
    input KEY1, //按键1
    output reg [6:0] SEG, //数码管显示数据
    output reg [1:0] SEL //位选信号
);

reg [7:0] cnt; //计数器

//时钟上升沿计数
always @(posedge CLK) begin
    if (RST) //复位信号有效
        cnt <= 0;
    else if (KEY0) //按键0有效
        cnt <= (cnt == 99) ? 0 : cnt + 1;
    else if (KEY1) //按键1有效
        cnt <= (cnt == 0) ? 99 : cnt - 1;
end

//数码管动态显示
integer i;
reg [1:0] digit;
reg [6:0] code [0:9]; //数码管段码表
initial begin
    code[0] = 7'b111_1110;
    code[1] = 7'b011_0000;
    code[2] = 7'b110_1101;
    code[3] = 7'b111_1001;
    code[4] = 7'b011_0011;
    code[5] = 7'b101_1011;
    code[6] = 7'b101_1111;
    code[7] = 7'b111_0000;
    code[8] = 7'b111_1111;
    code[9] = 7'b111_1011;
end
always @(posedge CLK) begin
    if (RST) //复位信号有效
        digit <= 2'b00;
    else begin
        if (digit == 2'b01) //个位
            SEG <= code[cnt % 10];
        else //十位
            SEG <= code[cnt / 10];
        for (i = 0; i < 500; i = i + 1) //延时
            SEL <= digit;
        digit <= (digit == 2'b01) ? 2'b00 : 2'b01; //切换位选信号
    end
end

endmodule

以下是检测功能的testbench测试文件代码：

module testbench;

reg CLK;
reg RST;
reg KEY0;
reg KEY1;
wire [6:0] SEG;
wire [1:0] SEL;

counter c(CLK, RST, KEY0, KEY1, SEG, SEL);

initial begin
    CLK = 0;
    RST = 1;
    KEY0 = 0;
    KEY1 = 0;
    #10 RST = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    KEY0 = 1;
    #10 KEY0 = 0;
    #100;
    KEY1 = 1;
    #10 KEY1 = 0;
    #100;
    $finish;
end

always #5 CLK = ~CLK;

endmodule

该测试文件模拟了按下抬起按键的过程，通过检查数码管的显示结果来验证计数器的功能是否正确。