| US 7,475,297 B1 | ||
| Efficient method for computing clock skew without pessimism | ||
| Walter A. Manaker, Jr., Boulder, Colo. (US) | ||
| Assigned to XILINX, Inc., San Jose, Calif. (US) | ||
| Filed on Nov. 24, 2004, as Appl. No. 10/997,565. | ||
| Int. Cl. G11B 20/20 (2006.01); G06F 17/50 (2006.01) | ||
| U.S. Cl. 714—700 [716/6; 716/10; 716/16] | 15 Claims |
| 1. A method for determining a setup skew, comprising:
determining a nearest common ancestor (NCA) in a clock distribution network, which NCA is an ancestor node for a plurality
of descendant nodes including a destination node and a source node;
determining minimum and maximum NCA clock delays for the NCA;
determining a minimum clock delay for the destination node and subtracting the minimum NCA clock delay to determine a destination
node minimum delta clock delay;
determining a maximum clock delay for the source node and subtracting the maximum NCA clock delay to determine a source node
maximum delta clock delay;
subtracting the source node maximum delta clock delay from the destination node minimum delta clock delay to determine the
setup skew between the source and destination nodes;
wherein determining the NCA comprises determining a list of ancestors each having a set of descendant nodes, wherein each
set includes both the source and the destination node.
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