从零开始学习 UVM4.1UVM Phases —— UVM Phases 介绍

Posted 2023-04-05 ReRrain

文章目录

• • UVM Phases是什么？
  • UVM主要phase
  • 为什么 build 从上往下？
  • 为什么Verilog TestBench不需要 Phase 机制？
  • 为什么SystemVerilog TestBench需要Phases？
  • 每个 UVM Phase应该做什么？

UVM Phases是什么？

所有TestBench组件都是从uvm_component派生的，并且具有 Phase 概念。每个组件都经历一组预定义（pre-defined）的phases，直到所有组件在当前phase执行完毕后，它才能进入下一个phase。因此，UVM阶 phase在仿真生命周期中充当同步机制（synchronizing mechanism）。

由于各个Phase被定义为回调函数，所以从uvm_component派生的类可以在回调方法中执行有用的工作。不消耗仿真时间的方法是函数，而消耗仿真时间的方法则是任务。所有阶段可以分为三类：

• 1. 构建时期（Build time phases）
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UVM中的class

UVM中的类包括：基类(base)------------uvm_void/uvm_object/uvm_transaction/uvm_root/uvm_phase/uvm_port_base

                        报告(reporting)--------uvm_report_object/uvm_report_handler/uvm_report_server/uvm_report_catcher

                        Factory---------uvm_*_register/uvm_factory

                        配置(config)------uvm_resource/uvm_resoure_db/uvm_config_db

                        sequencer--------uvm_sequencer_base/uvm_sequencer_param/uvm_squencer/uvm_push_sequencer

                        sequence--------uvm_sequence_item/uvm_sequence_base/uvm_sequence

                        sychronization------uvm_event/uvm_event_callback/uvm_barrier/uvm_objection/uvm_heartbeat

                        containers----------uvm_pool/uvm_queue

                        TLM

                        component--------uvm_component/uvm_callback/uvm_test/uvm_env/uvm_agent/uvm_monitor/uvm_scoreboard/

                                                  uvm_driver/uvm_push_driver/uvm_random_stimulus/uvm_subscriber/comparators

                         Reg model

                         Macro

                         Commamd Line

1)uvm_void(virtual)---一个没有member和function的纯虚类。所有class的基类。

2)uvm_object(virtual)---data和component的基类，定义了一系列常用操作

                                    virtual function：get_name/get_full_name/get_inst_id/do_copy/create

                                    function：copy/compare/pack/pack_bytes

3)uvm_transaction(virtual)------variable：events-----event pool中为该transaction instance的event

                                                             begin_event/end_event

                                               function：get_event_pool/set_initiator(initiator of this transaction)/get_initiator

                                                              is_active

4)uvm_root------所有uvm的潜在top-level,同时控制整个phase的执行。

                         virtual methods：run_test(+testname)或者cmd中加+UVM_TESTNAME=

                         function：print_topology/set_timeout

                         variable：uvm_top------const uvm_root uvm_top = uvm_root::get()

5)uvm_phase------用户可以extend自己的phase，基类(uvm_task_phase/uvm_topdown_phase/uvm_bottomup_phase)

                                                                          (build phase是topbottom phase，connect是bottomtop phase)

                            virtual function：raise_objection/drop_objection/ exec_func/exec_task(CB)

                            function：jump

                            (new的时候，会有uvm_objection的类型传递)

 

uvm_factory用来创建UVM中的object和component,通过typedef和macro invocation来实现。

6)uvm_component_registry#(T,Tname)--------virtual function：get_type_name

                                                  static function：create/set_type_override/set_inst_override

7)uvm_object_registry#(T,Tname)--------virtual function：get_type_name

                                                  static function：create/set_type_override/set_inst_override

8)uvm_factory--------function：set_inst_override_by_type/set_inst_override_by_name/

                                              set_type_override_by_type/set_type_override_by_name/

                                              create_object_by_type/create_component_by_type/

                                              create_object_by_name/create_component_by_name/

Configuration和Resource Class，提供一个database，供读写。通过queues的方式，可以保存scalar/class handle/

                    queues/list/virtual interface的结构，保存三部分内容name_table, type_table, set_of scope(通过expression实现)

uvm_resource_db：较低水平的resource database

uvm_config_db：较高水平的resource database，提供configuration的interface

9) virtual class uvm_resource_base--------task：wait_modified()

                                                             function：set_scope()

10)uvm_resource_pool--------static function：get()

                                                    funciton：set()/set_override()/set_name_override()/set_type_override()

                                                                   lookup_name()/get_by_name()

11)uvm_resoure #(T)-----------function： read/write()/set/get_by_name/get_by_type

12)uvm_resoure_db #(T)-----------function：/set/get_by_name/get_by_type

13)uvm_config_db #(T)-----------static function：get()/set()/exist()/wait_modified()

 

uvm_event对SV中的event类型的一次封装：

14)uvm_event---------virtual task wait_on/wait_off/wait_trigger

                                 virtual function reset/add_callback

15)uvm_event_callback(virtual)-------virtual function pre_trigger/post_trigger(uvm_event e, uvm_object data = null)

16)uvm_barrier-------virtual task wait_for()

                                virtual function reset()/set_threshold/get_threshold/cancel

uvm_objection的class，提供end_of_test的机制。

17)uvm_objection------virtual function raise_objection/drop_objection/raised/dropped/set_drain_time

 

Container class，针对SV中的queue和associative array做的封装。

18)uvm_pool #(type KEY = int, T = uvm_void)-----------get/add/num/delete/first/last/nect/prev

19)uvm_queue #(T)