11 sequence items in UVM

所有用户定义的sequence items都是从 uvm_sequence_item 类扩展的，因为它利用生成激励并具有sequence-sequencer机制的控制功能。

11.1 uvm_sequence_item class hierarchy

如上图所示，uvm_sequence_item派生自uvm_transaction类。

它支持UVM object章节中讨论的所有方法，如copy, compare, clone, print等。

11.2 uvm_sequence_item example

class seq_item extends uvm_seqeunce_item;
  rand int        value;
  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