class - 参数化类和多态性

Question

我想知道是否有更好更直接的方法来对从参数化类生成的一组类使用多态性。
以下系统 verilog 代码有效。有没有更优雅的方式？编辑:我可以在 C++ 中实现类似的东西吗？

`define OVERRIDE_PARAMETER_CPU parameter WIDTH=32 ;
`define OVERRIDE_PARAMETER_GFX parameter WIDTH=16 ;     

class Req #(parameter WIDTH=8);
    bit[WIDTH-1:0]  Address;
    virtual function Print;
        $display("Generic: %x[%0d]",Address,WIDTH);
    endfunction
endclass

typedef Req#(8) generic_req ;

class CPU_Req extends generic_req;  
    `OVERRIDE_PARAMETER_CPU
    function Print;
        $display("CPU: %x[%0d]",Address,WIDTH);
    endfunction
endclass

class GFX_Req extends generic_req;          
    `OVERRIDE_PARAMETER_GFX
    function Print;
        $display("GFX: %x[%0d]",Address,WIDTH);
    endfunction
endclass


program Test ;

    generic_req Req_Q[$],Temp,Generic_Req;    
    CPU_Req     C_Req;
    GFX_Req     G_Req;

    initial
    begin
        C_Req=new();
        G_Req=new();
        Generic_Req=new();
        C_Req.Address=32'h1234;
        G_Req.Address=32'hFF;
        Generic_Req.Address=32'h0;

        Req_Q.push_back(Generic_Req);
        Req_Q.push_back(C_Req);
        Req_Q.push_back(G_Req);

        while(Req_Q.size()!=0)
        begin
            Temp=Req_Q.pop_front();
            Temp.Print();
        end    
    end    
endprogram

Answer 1

我对您的代码做了一些更改。我不确定这是否是你要找的。

class Req #(parameter WIDTH=8);
   bit[WIDTH-1:0]  Address;
   virtual function void Print;
      $display("Generic: %x[%0d]",Address,WIDTH);
   endfunction
endclass

//class CPU_Req extends generic_req;  
class CPU_Req #(parameter WIDTH=16) extends Req#(WIDTH);
     function void Print;
        $display("CPU: %x[%0d]",Address,WIDTH);
     endfunction
endclass

class GFX_Req #(parameter WIDTH=24) extends Req#(WIDTH);          
     function void Print;
        $display("GFX: %x[%0d]",Address,WIDTH);
     endfunction
endclass


program Test ;

   Req            Generic_Req;
   CPU_Req #(32)  C_Req32;
   CPU_Req        C_Req16;
   GFX_Req #(128) G_Req128;

   initial
     begin
        C_Req32     = new();
        C_Req16     = new();
        G_Req128    = new();
        Generic_Req = new();

        C_Req32.Address  = 32'h12345678;
    C_Req16.Address  = 32'h12345678;
        G_Req128.Address = {2{64'h1234_5678_9ABC_DEF0}};
        Generic_Req.Address=32'h12345678;

    C_Req32.Print();
    C_Req16.Print();
    G_Req128.Print();
    Generic_Req.Print();

     end    
endprogram

结果:

# CPU: 12345678[32]
# CPU: 5678[16]
# GFX: 123456789abcdef0123456789abcdef0[128]
# Generic: 78[8]