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

DescriptionQ118

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Q118DVFollow-up to Q117ASIC interview problem

Cover arbitrary type and priority values

TechniquesDVAssociative arraySparse coverageExpected domain

DifficultyMedium

TopicFunctional Coverage

LanguageSystemVerilog

Requirements5 checkpoints

Problem

Types and priorities are arbitrary integer values rather than contiguous ranges starting at zero. Track their cross and determine when every pair from the declared expected sets has been observed.

Class declarationSystemVerilog

class SparseCoverageGapDetector;
  function void add_expected_type(int value);
  function void add_expected_priority(int value);
  function void sample(int type_value, int priority_value);
  function bit all_combinations_hit();
endclass

Example input and output

Use this case to check your interpretation

Input

expected types={2,7}, priorities={1,9}; sample (2,1),(7,9), then invalid (3,1)

Output

first_missing=(2,9); invalid sample rejected; all_hit=0

Explanation

The sparse universe is the declared Cartesian product, not values inferred from traffic; type 3 lies outside that universe.

Requirements (5)

Receive finite expected type and priority sets and de-duplicate their values.
Store observed pairs sparsely in associative arrays.
Reject samples containing a value outside either expected set.
Support all-hit and first-missing queries.
Do not infer the expected universe from observed traffic.