6 UVM Object

uvm_object类是所有uvm层次类的基类，如uvm_report_object、uvm_component、uvm_transaction、uvm_sequence_item、uvm_sequence等。它在定义一组方法（如create, copy, print, clone, compare, record等）方面起着重要作用。

6.1?UVM Utility Macros and field macros

我们在UVM factory章节已经看到了“create”方法是如何工作的，“create”方法为对象分配内存空间并返回相同类型的句柄。

`uvm_object_utils或`uvm_abject_utils_begin`uvm_object_utils_end宏用于在uvm工厂中注册uvm_object和其他派生类型，如uvm_transaction、uvm_sequece_items。

UVM字段宏(field macros)提供了?create, copy, print, clone, compare, record等方法的实现。工厂中有不同的`uvm_field_*宏可用于各种数据类型变量的注册。`uvm_field_*宏至少接受两个参数作为arg（与`uvm_field_*宏兼容的变量的实例名）和flag（用作添加相应数据方法的控制机制）。

new()方法很重要，可以用相应的类名作为扩充来定义。

注：在编译期间，这些UVM自动化宏扩展了相应宏可用的完整代码。

Syntax without?field macros:

`uvm_object_utils(<class Type>)

Syntax with?field macros:

`uvm_object_utils_begin(<class_type>)
  `uvm_field_*(<arg>, <flag>)
`uvm_object_utils_end

以下字段宏通常用于标量/动态类属性的数据方法[data methods]（copy, compare, pack, unpack, print, clone,?等）。可以从UVM参考文件中研究完整列表。?

6.1.1?`uvm_field_* macros

`uvm_field_*宏实现标量属性的数据方法。

6.1.2 `uvm_field_sarray_* macros

`uvm_field_sarray*宏实现一维静态数组属性的数据方法。

6.1.3 `uvm_field_array_* macros

uvm_field_array*宏实现一维动态数组属性的数据方法。

6.1.4 `uvm_field_* macro flag

也可以指定打印的进制。默认是16进制HEX。

6.2 Code with `uvm_object_utils

typedef enum{RED, GREEN, BLUE} color_type;
class my_object extends uvm_object;
  int        o_var;
  string     o_name;
  color_type colors;
  byte       data[4];
  bit [7:0]  addr;
  
  `uvm_object_utils(my_object)
  
  function new(string name = "my_object");
    super.new(name);
  endfunction
endclass

6.3 Code with `uvm_object_utils_begin and `uvm_object_utils_end

typedef enum{RED, GREEN, BLUE} color_type;
class my_object extends uvm_object;
  rand int        value;
       string     names;
  rand color_type colors;
  rand byte       data[4];
  rand bit [7:0]  addr;
  
  `uvm_object_utils_begin(my_object)
    `uvm_field_int(value, UVM_ALL_ON)
    `uvm_field_string(names, UVM_ALL_ON)
    `uvm_field_enum(color_type, colors, UVM_ALL_ON)
    `uvm_field_sarray_int(data, UVM_ALL_ON)
    `uvm_field_int(addr, UVM_ALL_ON)
  `uvm_object_utils_end
  
  function new(string name = "my_object");
    super.new(name);
  endfunction
endclass

6.4 UVM中的打印方法

打印方法用于以格式良好的方式深度打印UVM对象类的属性。需要根据类属性的数据类型使用适当的`uvm_field_*宏。

注意：sprint()方法与print()方法相同，不同的是sprint()方法以字符串格式打印对象。

6.4.1 打印方法示例

typedef enum{RED, GREEN, BLUE} color_type;

class temp_class extends uvm_object;
  rand bit [7:0] tmp_addr;
  rand bit [7:0] tmp_data;
  
  function new(string name = "temp_class");
    super.new(name);
  endfunction
  
  `uvm_object_utils_begin(temp_class)
    `uvm_field_int(tmp_addr, UVM_ALL_ON)
    `uvm_field_int(tmp_data, UVM_ALL_ON)
  `uvm_object_utils_end
endclass

class my_object extends uvm_object;
  rand int        value;
       string     names;
  rand color_type colors;
  rand byte       data[4];
  rand bit [7:0]  addr;
  rand temp_class tmp;
  
  `uvm_object_utils_begin(my_object)
    `uvm_field_int(value, UVM_ALL_ON)
    `uvm_field_string(names, UVM_ALL_ON)
    `uvm_field_enum(color_type, colors, UVM_ALL_ON)
    `uvm_field_sarray_int(data, UVM_ALL_ON)
    `uvm_field_int(addr, UVM_ALL_ON)
    `uvm_field_object(tmp, UVM_ALL_ON)
  `uvm_object_utils_end
  
  function new(string name = "my_object");
    super.new(name);
    tmp = new();
    this.names = "UVM";
  endfunction
endclass

class my_test extends uvm_test;
  `uvm_component_utils(my_test)
  my_object obj;
  bit packed_data_bits[];
  byte unsigned packed_data_bytes[];
  int unsigned packed_data_ints[];
  
  my_object unpack_obj;
  
  function new(string name = "my_test", uvm_component parent = null);
    super.new(name, parent);
  endfunction
  
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    obj = my_object::type_id::create("obj", this);
    assert(obj.randomize());
    obj.print();
    // or
    //`uvm_info(get_full_name(), $sformatf("obj = \n%s", obj.sprint()), UVM_LOW);
  endfunction
endclass

module tb_top;
  initial begin
    run_test("my_test");
  end
endmodule

Output:

UVM_INFO @ 0: reporter [RNTST] Running test my_test...
--------------------------------------------
Name          Type          Size  Value     
--------------------------------------------
obj           my_object     -     @349      
  value       integral      32    'h1f135537
  names       string        3     UVM       
  colors      color_type    32    GREEN     
  data        sa(integral)  4     -         
    [0]       integral      8     'h9f      
    [1]       integral      8     'h33      
    [2]       integral      8     'h12      
    [3]       integral      8     'h9c      
  addr        integral      8     'h2f      
  tmp         temp_class    -     @350      
    tmp_addr  integral      8     'h39      
    tmp_data  integral      8     'hbd      
--------------------------------------------

6.4.2 print method with `uvm_object_utils

如果print方法与`uvm_object_utils一起使用，则不会打印类属性。

typedef enum{RED, GREEN, BLUE} color_type;
class my_object extends uvm_object;
  rand int        o_var;
       string     o_name;
  rand color_type colors;
  rand byte       data[4];
  rand bit [7:0]  addr;
  
  `uvm_object_utils(my_object)
  
  function new(string name = "my_object");
    super.new(name);
  endfunction
endclass

class my_test extends uvm_test;
  `uvm_component_utils(my_test)
  my_object obj;
  
  function new(string name = "my_test", uvm_component parent = null);
    super.new(name, parent);
  endfunction
  
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    obj = my_object::type_id::create("obj", this);
    assert(obj.randomize());
    obj.print();
  endfunction
   
  function void end_of_elaboration_phase(uvm_phase phase);
    super.end_of_elaboration_phase(phase);
    uvm_top.print_topology();
  endfunction
endclass

module tb_top;
  initial begin
    run_test("my_test");
  end
endmodule

Output:

UVM_INFO @ 0: reporter [RNTST] Running test my_test...
----------------------------
Name  Type       Size  Value
----------------------------
obj   my_object  -     @1872
----------------------------
UVM_INFO /xcelium20.09/tools//methodology/UVM/CDNS-1.2/sv/src/base/uvm_root.svh(605) @ 0: reporter [UVMTOP] UVM testbench topology:
----------------------------------
Name          Type     Size  Value
----------------------------------
uvm_test_top  my_test  -     @1805
----------------------------------

6.4.3 do_print() method

UVM自动化宏主要涉及许多影响仿真器性能的附加代码。因此，不建议使用。相反，do_print()回调方法是一个用户定义的钩子，由print()或sprint()方法调用。用户必须调用在do_print()实现的printer API来添加要打印的信息。

6.4.3.1 do_print() method example

typedef enum{RED, GREEN, BLUE} color_type;

class temp_class extends uvm_object;
  rand bit [7:0] tmp_addr;
  rand bit [7:0] tmp_data;
  
  function new(string name = "temp_class");
    super.new(name);
  endfunction
  
  `uvm_object_utils(temp_class)
    
  function void do_print(uvm_printer printer);
    super.do_print(printer);
    printer.print_field_int("tmp_addr", tmp_addr, $bits(tmp_addr), UVM_HEX);
    printer.print_field_int("tmp_data", tmp_data, $bits(tmp_data), UVM_HEX);
  endfunction
endclass

class my_object extends uvm_object;
  rand int        value;
       string     names = "UVM";
  rand color_type colors;
  rand byte       data[4];
  rand bit [7:0]  addr;
  rand temp_class tmp;
  
  `uvm_object_utils(my_object)
  
  function new(string name = "my_object");
    super.new(name);
    tmp = new();
  endfunction
  
  function void do_print(uvm_printer printer);
    super.do_print(printer);
    printer.print_field_int("value", value, $bits(value), UVM_HEX);
    printer.print_string("names", names);
    printer.print_string("colors", colors.name);
    foreach(data[i])
      printer.print_field_int($sformatf("data[%0d]", i), data[i], $bits(data[i]), UVM_HEX);
    printer.print_field_int("addr", addr, $bits(addr), UVM_HEX);
    printer.print_object("tmp", tmp);
  endfunction
endclass

class my_test extends uvm_test;
  `uvm_component_utils(my_test)
  my_object obj;
  
  function new(string name = "my_test", uvm_component parent = null);
    super.new(name, parent);
  endfunction
  
  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    obj = my_object::type_id::create("obj", this);
    assert(obj.randomize());
    obj.print();
  endfunction
endclass

module tb_top;
  initial begin
    run_test("my_test");
  end
endmodule

Output:

UVM_INFO @ 0: reporter [RNTST] Running test my_test...
------------------------------------------
Name          Type        Size  Value     
------------------------------------------
obj           my_object   -     @1876     
  value       integral    32    'ha4a4f87e
  names       string      3     UVM       
  colors      string      3     RED       
  data[0]     integral    8     'hc6      
  data[1]     integral    8     'h4c      
  data[2]     integral    8     'hf       
  data[3]     integral    8     'h89      
  addr        integral    8     'h53      
  tmp         temp_class  -     @1878     
    tmp_addr  integral    8     'hea      
    tmp_data  integral    8     'hdf      
------------------------------------------