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

DescriptionQ828

Page ↗

Q828DVGoogleASIC interview problem

Match out-of-order responses by ID

TechniquesDVUVMScoreboardOut-of-orderAssociative array

DifficultyMedium

TopicUVM

LanguageSystemVerilog

Requirements4 checkpoints

Problem

Requests use unique 8-bit IDs, and responses may return in any order. Build an ID-indexed scoreboard for operand-squared results, duplicate detection, exact comparison, and end-of-test leftovers.

Starting declarationSystemVerilog

req: id[7:0], operand[15:0]
rsp: id[7:0], result[31:0]
expected result = operand * operand
maximum 32 outstanding requests

Example input and output

Use this case to check your interpretation

Input

Requests (1,3), (2,4); responses (2,16), (1,9)

Output

Both responses pass and the associative array becomes empty

Explanation

Each response is matched by ID rather than arrival position.

Requirements (4)

On each request, compute the expected result and store it in an associative array indexed by ID; reject a duplicate outstanding ID.
On each response, require the ID to exist, compare result exactly, then delete that ID after the comparison.
Report an unexpected ID, duplicate request ID, data mismatch, and any entries still present at end of test as distinct errors.
Do not compare responses by arrival order; the only ordering key is the response ID.