uvm_do/ovm_do vs start_item/finish_item

uvm_do/ovm_do

	// From `uvm_do
	// For a sequence item, the following are called, in order
	`uvm_create(item)
	sequencer.wait_for_grant(prior) (task)
	this.pre_do(1) (task)
	item.randomize()
	this.mid_do(item) (func)
	sequencer.send_request(item) (func)
	sequencer.wait_for_item_done() (task)
	this.post_do(item) (func)
	// For a sequence, the following are called, in order
	`uvm_create(sub_seq)
	sub_seq.randomize()
	sub_seq.pre_start() (task)
	this.pre_do(0) (task)
	this.mid_do(sub_seq) (func)
	sub_seq.body() (task)
	this.post_do(sub_seq) (func)
	sub_seq.post_start() (task)

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start_item/finish_item

	//The sequence-item execution flow looks like
	//
	//User code
	//
	// parent_seq.start_item(item, priority);
	// item.randomize(...) [with {constraints}];
	// parent_seq.finish_item(item);
	sequencer.wait_for_grant(prior) (task) \ start_item \
	parent_seq.pre_do(1) (task) / \
	`uvm_do* macros
	parent_seq.mid_do(item) (func) \ /
	sequencer.send_request(item) (func) \ finish_item /
	sequencer.wait_for_item_done() (task) /
	parent_seq.post_do(item) (func) /
	//Attempting to execute a sequence via <start_item>/<finish_item>
	//will produce a run-time error.

view raw uvm_do_vs_start_item_finish_item_2.sv hosted with ❤ by GitHub

Reference: 
1) uvm_sequence_defines.svh
2) uvm_sequence_base.svh