Patent ID: 7793247
Filing Date: 2010-09-07
Classification: G06F

Abstract:
1. A computer-implemented method of implementing a circuit design for an integrated circuit, comprising: identifying, using a computer, matching elements and non-matching elements between an original version of the circuit design and a modified version of the circuit design, the original version having an original implementation; partially placing and routing the modified version to establish a guided implementation having guided placements and guided routes for the matching elements copied from placements and routes from the original implementation; obtaining actual timing characteristics for the guided placements and the guided routes; before placing and routing the non-matching elements, determining timing-critical ones of the matching elements in the modified version using the actual timing characteristics; wherein, whether or not a matching element is determined to be timing critical controls whether a weak lock or a strong lock is applied to the matching element; before placing and routing the non-matching elements of the modified version, applying a weak lock to each of the matching elements, wherein placement of a matching element having a weak lock is recommended, but changeable if another location is determined to reduce signal delays during placing and routing of the of the non-matching elements; after determining the timing-critical elements and before placing and routing the non-matching elements, applying a strong lock to the matching elements that are not timing-critical elements, wherein a weak lock of an element is transformed to strong lock if the element is identified as not timing-critical, and wherein placement of an element having a strong lock is maintained unless swapping its position with a timing-critical element would reduce signal delays; and completing placement and routing of the modified version using the computer by initially maintaining each of the guided placements that is not one of the timing-critical elements.