`timescale1ns/1ns module test;// 这个简单示例展示了如何使用 uvm_test_done 异议机制来协调测试结束活动。// 若想了解在完整环境中使用测试结束协调的示例，请参考 xbus 示例。//// 在本例中，组件设置了一个 10 时间单位的排空时间（drain time）。// 组件随后启动了 4 个进程，这些进程消耗不同的时间。// 当最后一个进程完成（时间为 50）时，排空时间开始生效。// 测试在时间 60 结束。//// 该示例还展示了组件异议回调的用法。// 本例中使用了 dropped 回调，但 raised 和 all_dropped 的工作方式类似，// 只是 all_dropped 是一个耗时的任务。import uvm_pkg::*;`include"uvm_macros.svh"classsimple_testextends uvm_test;functionnew(string name,uvm_component parent);super.new(name,parent);endfunction:new// Register with the factory.`uvm_component_utils(simple_test)virtualtaskrun_phase(uvm_phase phase);// Set a drain time on the objection if neededuvm_report_info("drain","Setting drain time of 10",UVM_NONE);uvm_test_done.set_drain_time(this,10);// Run a bunch of processes in parallelforkdoit(35);doit(25);doit(50);doit(15);join endtask// A simple task that consumes some time.taskdoit(time delay);staticints_inst=0;intinst=s_inst++;//Raise an objection before starting the activityuvm_test_done.raise_objection(this);uvm_report_info("doit",$sformatf("Starting doit (%0d) with delay %0t",inst,delay),UVM_NONE);#delay;uvm_report_info("doit",$sformatf("Ending doit (%0d)",inst),UVM_NONE);//Drop the objection when doneuvm_test_done.drop_objection(this);endtask// Use an objection callback do something when objections are raised or// dropped (or all dropped). This example prints some information on each// drop.virtualfunctionvoiddropped(uvm_objection objection,uvm_object source_obj,string description,intcount);uvm_report_info("dropped",$sformatf("%d objection(s) dropped from %s, total count is now %0d",count,source_obj.get_full_name,objection.get_objection_total(this)),UVM_NONE);endfunction endclass:simple_test// Run the testinitialrun_test("simple_test");endmodule 以下是实际仿真结果：--------------------------------------------------------
