Skip to question
asic.fyi

Hardware interview practice

Fix event-loss and shared-state monitor bugs

MediumVerificationSystemVerilog

A monitor starts waiting for interrupt only after write_start, but an earlier interrupt must cancel the next write. Concurrent task calls also share static locals. Identify and fix both bugs.

Starting point

Question code

// Events: write_start, interrupt, reset
// Multiple re-entrant monitor calls may be active.
Reviewed example

Work through one case

Input
interrupt at cycle 5; write_start at cycle 6
Expected output
The cycle-6 write is canceled and the pending interrupt is consumed

A lifetime interrupt collector preserves the event before any write-specific task starts.

What to cover

Requirements

  1. Capture interrupts continuously in persistent state or a queue.
  2. Atomically consume a pending interrupt when a write begins.
  3. Use automatic per-call storage or transaction objects.
  4. Define reset to clear pending interrupts and cancel active work deterministically.
Continue practicing
SystemVerilog SchedulingReason about same-region forked output order