2.2.4. Recovery and Removal Analysis
For example, signals such as clear and preset must be stable before the next active clock edge. The recovery slack calculation is similar to the clock setup slack calculation, but the calculation applies to asynchronous control signals.
Removal time is the minimum length of time the deassertion of an asynchronous control signal must be stable after the active clock edge. The Timing Analyzer removal slack calculation is similar to the clock hold slack calculation, but the calculation applies to asynchronous control signals.
If the asynchronous reset signal is from a device pin, you must create an input delay constraint to the asynchronous reset pin for the Timing Analyzer to perform removal analysis on the path.