Skip to the selected question
ASIC.FYI

ASIC Question Bank

1,000+ hardware interview questions
Question bank1110 results
  1. Easy
  2. Easy
  3. Medium
  4. Medium
  5. Medium
  6. Medium
  7. Easy
  8. Easy
  9. Easy
  10. Easy
  11. Easy
  12. Easy
  13. Easy
  14. Easy
  15. Medium
  16. Easy
  17. Medium
  18. Easy
  19. Hard
  20. Medium
  21. Medium
  22. Easy
  23. Medium
  24. Medium
  25. Medium
  26. Easy
  27. Medium
  28. Medium
  29. Easy
  30. Easy
  31. Medium
  32. Medium
  33. Hard
  34. Easy
  35. Medium
  36. Hard
  37. Easy
  38. Medium
  39. Hard
  40. Medium
  41. Medium
  42. Easy
  43. Medium
  44. Medium
  45. Medium
  46. Easy
  47. Hard
  48. Easy
  49. Easy
  50. Easy
DescriptionQ023
Page ↗
Q023DVASIC interview problem

Match out-of-order packets by ID

TechniquesScoreboardOut-of-orderID matchingAssociative array
DifficultyMedium
TopicReference Models
LanguageSystemVerilog
Requirements4 checkpoints
01

Problem

Implement a scoreboard for responses that may arrive in any cross-ID order while preserving order within each ID. Support more than one outstanding packet with the same ID.

Scoreboard architecture with a FIFO of expected packets for each transaction ID and out-of-order actual responses matched within each ID.
The per-ID queues preserve order within an ID while allowing different IDs to complete out of order.

Example input and output

Use this case to check your interpretation
Input
expected: id1=A, id1=B, id2=C; responses: id2=C, id1=A, id1=B
Output
all three match; per-ID queues empty
Explanation

Cross-ID reordering is legal, but the two id1 responses still consume A before B from that ID's FIFO.

02

Requirements (4)

  • Store a FIFO of expected transactions for every ID instead of one value per ID.
  • Reject an output whose ID has no pending expectation.
  • Compare with the oldest expected packet for that ID and remove it only after selecting it.
  • Report every nonempty per-ID queue at end of test.