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

DescriptionQ641

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Q641DVASIC interview problem

Find an associative-array value without a sentinel

TechniquesDVSystemVerilogAssociative arraySparse traversalAPI design

DifficultyMedium

TopicSystemVerilog Data Structures

LanguageSystemVerilog

Requirements4 checkpoints

Problem

A reference model stores int values at byte keys, and every byte value including 8'hFF is legal. Return a success flag separately from the first key whose value matches a target.

Starting declarationSystemVerilog

int mem[byte];

function bit find_value(input int target, output byte key);

Example input and output

Use this case to check your interpretation

Input

mem = '{8'hFF: 3}, target = 3

Output

success = 1, key = 8'hFF

Explanation

The all-ones key remains representable because success is carried independently rather than encoded as an impossible byte value.

Requirements (4)

Return failure cleanly for an empty associative array.
Visit each existing key at most once using first() and next().
Return the first matching key in associative index order.
Use the function result as the success indicator instead of reserving a key as a sentinel.