1,000+ ASIC Interview Questions: SystemVerilog, UVM & RTL

DescriptionQ861

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Q861DVNVIDIAASIC interview problem

Share a named UVM configuration event

TechniquesDVSystemVerilogUVMShareA

DifficultyMedium

TopicSystemVerilog and UVM

LanguageSystemVerilog

Requirements4 checkpoints

Problem

A producer and consumer are created independently but must rendezvous through the global UVM event pool after configuration is published. Write the two UVM tasks that publish and consume a version number without missing an early trigger.

Class declarationSystemVerilog

class cfg_version_obj extends uvm_object; int unsigned version; endclass
task publish_cfg(int unsigned version);
task wait_cfg(output int unsigned version);

Example input and output

Use this case to check your interpretation

Input

Start wait_cfg first, then call publish_cfg(7) using the shared global event.

Output

wait_cfg returns version = 7.

Explanation

Both tasks resolve the same named event, and the trigger data carries the published version object to the waiter.

Requirements (4)

Both tasks obtain the same uvm_event from uvm_event_pool::get_global_pool().get("cfg_done").
publish_cfg creates cfg_version_obj, fills its version, and triggers the event once with that object.
wait_cfg uses wait_on so a trigger that happened before the task began is still observed, then reads the stored trigger data.
The producer never resets the event; only the test resets it between test cases after both tasks finish.