sequence的启动方式

• start启动

my_sequence my_seq;
my_seq = my_sequence::type_id::create("my_seq");
my_seq.start(sequencer);

• default启动（factory机制例化）

uvm_config_db#(uvm_object_wrapper)::set(this,
                                        "env.i_agt.sqr.main_phase",
                                        "default_sequence",
                                        case0_sequence::type_id::get());

• default启动（先实例化）

function void my_case0::build_phase(uvm_phase phase);
  case0_sequence cseq;
  super.build_phase(phase);

  cseq = new("cseq");
  uvm_config_db#(uvm_sequence_base)::set(this,
                                         "env.i_agt.sqr.main_phase",
                                         "default_sequence",
                                         cseq);
endfunction