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

DescriptionQ258

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Q258DVASIC interview problem

Verify a minimum energy-window engine

TechniquesDVSliding windowOut-of-orderTie-breakingCoverage

DifficultyMedium

TopicReference Models

LanguageSystemVerilog

Requirements5 checkpoints

Problem

Implement an exhaustive oracle and four-entry tagged scoreboard core for the shortest contiguous nonnegative energy window whose sum reaches a threshold.

Example input and output

Use this case to check your interpretation

Input

energy=[2,1,4,2]; threshold=6

Output

found=1; start=2; length=2

Explanation

Window [4,2] reaches six in two elements, shorter than [2,1,4], and no one-element window qualifies.

Requirements (5)

Build an exhaustive widened-arithmetic oracle and treat zero threshold or count above the configured maximum as a bad request.
Return found=0 with zero start and length when no window qualifies; otherwise compare shortest length before lowest start.
Store at most four predictions by transaction ID, compare and retire each response exactly once, and reject duplicate or unknown IDs.
Flush every pending prediction on reset and provide an end-of-test empty check for missing responses.
Identify exact-threshold hits, equal-length ties, zero density, response order, stalls, errors, and reset as follow-up coverage targets.