testbench——文件读入输出

注：仿真工具为ISE自带simulation

1.读入.txt中的文件

待读入文件为photo.txt，位于所建工程文件夹中。

代码：

integer cnt,i;
reg [7:0] mem[31:0];
reg [5:0] address;
integer fp;
initial
begin
	fp = $fopen("photo.txt","rb");
	address = 0;
    while(!$feof(fp))  begin 
        for(i=0; i<16; i=i+1)  begin
            cnt = $fscanf (fp, "%d",mem[address]);
            address=address+1;
        end
    end
    $fclose(fp);
end

注释：

使用句柄fp定位文件之后操作即可；

代码中i < 16的值原则上可以为任意值，一般小于文件中数据总数就好了，因为有 while(!$feof(fp)) 在控制；

以二进制方式读入的；

待读入数据：

结果图：

另外一种写法

reg [7:0] mem[31:0];
initial
begin
    $readmemh("photo.txt",mem);
end

注：$readmemh和$readmemb分别用来读入源文件为16进制和2进制的文件

结果图：

2.写出.txt文件

代码：

integer fp_write;
reg [5:0] write_address;
initial
begin
	fp_write =  $fopen("output.txt");
	write_address = 0;
	while(write_address != 32)
	begin
		$fwrite(fp_write, "%d ", mem[write_address]);
		write_address = write_address + 1;
		if(write_address%8 == 0) $fwrite(fp_write, "
");
	end
	$fclose(fp_write);
end

注：

if(write_address%8 == 0) $fwrite(fp_write, " "); 为了给文件中加入换行

结果：

整体代码：

`timescale 1 ns / 1 ps

module testbench;

reg clk, rst, start;

initial begin 
    clk = 0;
    forever #5 clk = ~clk;
end

initial begin
    rst = 0;
	#8 rst = 1;
end

initial begin
    start = 0;
    #502 start = 1;
end

integer cnt,i;
reg [7:0] mem[31:0];
reg [5:0] address;
integer fp;
initial
begin
	fp = $fopen("photo.txt","rb");
	address = 0;
    while(!$feof(fp))  begin 
        for(i=0; i<16; i=i+1)  begin
            cnt = $fscanf (fp, "%d",mem[address]);
            address=address+1;
        end
    end
    $fclose(fp);
end

integer fp_write;
reg [5:0] write_address;
initial
begin
	fp_write =  $fopen("output.txt");
	write_address = 0;
	while(write_address != 32)
	begin
		$fwrite(fp_write, "%d ", mem[write_address]);
		write_address = write_address + 1;
		if(write_address%8 == 0) $fwrite(fp_write, "
");
	end
	$fclose(fp_write);
end

endmodule