Verilog之$sreadmemb

1　　Memories 

　Memories file format is shown below, the address is specified as @ <address> 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.

 

2　　Syntax: 

　$readmemb ("<file_name>", <memory_name>"); 
　$readmemb ("<file_name>", <memory_name>, memory_start"); 
　$readmemb ("<file_name>", <memory_name>, memory_start, memory_finish");

　The memory_start and memory_finish are optional.

 

3　　　Example

　Now that a memory file exists to access it, it has to be initialised for memory reading. 

 1 module testmemory;  2     reg [7:0] memory [9:0];  3     integer index;  4 

 5     initial 

 6 　　 begin

 7         $readmemb("mem.dat", memory);  8         

 9         for(index = 0; index < 10; index = index + 1) 10         $display("memory[%d] = %b", index[4:0], memory[index]); 11      end

12 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