Incremental elmore delay calculation

A non-transitory computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method for incrementally updating a set of Elmore pin-to-pin delays for a routed net that electrically connects a driver pin to a set of load pins, the method comprising:

• receiving a representation of a physical topology of the routed net that electrically connects the driver pin to the set of load pins;
• computing a set of incremental Elmore delay coefficients based on the representation, wherein the incremental Elmore delay coefficients do not need to be changed as long as the physical topology of the routed net does not change;
• receiving a change in a capacitance of a load pin in the set of load pins;
• computing a set of incremental Elmore pin-to-pin delay adjustments based on the change in the capacitance and the set of incremental Elmore delay coefficients, wherein each incremental Elmore pin-to-pin delay adjustment is computed by multiplying a corresponding incremental Elmore delay coefficient with the change in the capacitance;
• and
• updating the set of Elmore pin-to-pin delays by adding each incremental Elmore pin-to-pin delay adjustment in the set of incremental Elmore pin-to-pin delay adjustments to a corresponding Elmore pin-to-pin delay in the set of Elmore pin-to-pin delays.

A computer system, comprising:

• a processor;
• and
• a non-transitory computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method for incrementally updating a set of Elmore pin-to-pin delays for a routed net that electrically connects a driver pin to a set of load pins, the method comprising:
• receiving a representation of a physical topology of the routed net that electrically connects the driver pin to the set of load pins;
• computing a set of incremental Elmore delay coefficients based on the representation, wherein the incremental Elmore delay coefficients do not need to be changed as long as the physical topology of the routed net does not change;
• receiving a change in a capacitance of a load pin in the set of load pins;
• computing a set of incremental Elmore pin-to-pin delay adjustments based on the change in the capacitance and the set of incremental Elmore delay coefficients, wherein each incremental Elmore pin-to-pin delay adjustment is computed by multiplying a corresponding incremental Elmore delay coefficient with the change in the capacitance;
• and
• updating the set of Elmore pin-to-pin delays by adding each incremental Elmore delay adjustment in the set of incremental Elmore pin-to-pin delay adjustments to a corresponding Elmore pin-to-pin delay in the set of Elmore pin-to-pin delays.