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← Temporal Language cs348 unit5new

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Showing Revision 1 created 04/12/2013 by Cogi-Admin.

  1. In the beginning of the unit, we've listed all the checks we wanted to
  2. implement to make sure our router is behaving correctly, or according to the F
  3. spec. One of them was the following. When we sent a packet with an incorrect
  4. parity, at some point within 15 cycles, the error signal of the router should
  5. go from zero to one, indicating that the router has recognized there was
  6. something wrong with the packet. We will implement this check using the
  7. temporal language and the temporal expression. All high-level verification
  8. languages have support for temporal expressions. They basically allow you to
  9. define sequences of events. You can say, I need to see this event, followed by
  10. another event within five cycles, followed by something else. So you can use
  11. these expressions to define your checks. So you basically define these
  12. sequences, and then you assert them. You say, "Okay, whenever there is activity
  13. on this interface These sequences should be obeyed. If there is anything wrong,
  14. stop the simulation and tell us about it. We could implement those checks
  15. writing our own state machines using TCMs, but this would create too much code,
  16. so temporal languages are very concise, they're very expressive, so we will use
  17. those. In the next exercise, we will define some events, and after that, we
  18. will implement our first temporal check.