Methods of estimating routing delays between two points in a programmable
logic device (PLD). The invention takes advantage of the fact that there
are a finite number of possible routes (routing paths) between any two
points in a PLD. In PLDs with a regular and tiled structure, such as
field programmable gate arrays, the number of routes between any two
points that are likely to be used by the router is relatively small.
Thus, given the locations of the two points to be connected, the route
most likely to be used by the router can be determined, and an associated
delay can be calculated. This associated delay is then reported as the
estimated routing delay. This method of delay estimation can be much more
accurate than using an average delay. When the delays between possible
paths vary widely, the actual delay of a connection can vary widely from
the average.