zoukankan      html  css  js  c++  java
  • Initialising Memories

     

    The file_name and memory_nameare memory_start and memory_finish are optional, it missed out they default to the start index of the named memory and the end of the named memory respectively.

    Memories can be stored in a file in the format shown below, the address is specified as @< address>, where the address is in hexadecimal.

            @003
            00000011
            00000100
            00000101
            00000110
            00000111
            00001000
            00001001
    

    With the above file it can be seen if the memory is large it would become very tedious to work out the address of a specific byte, so it is normally a good idea to use milestones along the memory file, so a larger file may look something like the following:

            @003
            00000011
            00000100
            00000101
            @006
            00000110
            00000111
            @008
            00001000
            00001001
    

    or if the data is contiguous, omit the address entirely.

    Now that a memory file exists to access it, it has to be initialised for memory reading. This can be done by the following.

            module testmemory;
               reg [7:0] memory [9:0];
               integer   index;
    
               initial begin
                  $readmemb("mem.dat", memory);
    
                  for(index = 0; index < 10; index = index + 1)
                  $display("memory[%d] = %b", index[4:0], memory[index]);
               end
            endmodule // testmemory
    

    with the file mem.data as

            1000_0001
            1000_0010
            0000_0000
            0000_0001
            0000_0010
            0000_0011
            0000_0100
            0000_0101
            0000_0110
            0000_0000
    

    EXERCISE

    Store the above data in a file and run the above programme

    Consider and understand the following code (run it to check):

            module fileDemo;
    
               integer   handle, channels, index, rand;
               reg [7:0] memory [15:0];
    
               initial begin
                  handle = $fopen("mem.dat");
                  channels = handle | 1;
                  $display("Generating contents of file mem.dat");
                  $fdisplay(channels, "@2");
    
                  for(index = 0; index < 14; index = index + 1) begin
                  rand = $random;
                  $fdisplay(channels, "%b", rand[12:5]);
                  end
    
                  $fclose(handle);
    
                  $readmemb("mem.dat", memory);
    
                  $display("
    Contents of memory array");
                  for(index = 0; index < 16; index = index + 1)
                  $displayb(memory[index]);
               end
    
            endmodule // fileDemo
    

    previous contents

  • 相关阅读:
    04-增删改查
    03-编写dao实现类方式
    02-基于注解的入门案例
    .net core api 图片上传与加载
    笔记一、数据库初始化 约定
    .net core MVC中级教程(四)
    .net core MVC中级教程(三)
    Windows 盘符映射
    c# 队列和堆栈
    isValidNode
  • 原文地址:https://www.cnblogs.com/touchblue/p/3537873.html
Copyright © 2011-2022 走看看