uvm总结，一共分这几大块
1.CDV
1.1cdv含义
1.2有约束的随机
2.component
3.TLM1.0
uvm tlm1.0
4.phase(component/objection)
uvm component phase
5.config_db
config_db/resource_db
6.factory
7.RAL
uvm RAL
8. sequence
uvm sequence
9. sequence_item/transaction
uvm sequence_item/transaction
