Patent ID: 7200828

Claim:
An automatic placement and routing apparatus to automatically perform placement and routing of a cell, based on original logical connection information, comprising: a cell origin logical connection information sampling part that receives after-modification logical connection information applied when said original logical connection information is modified, and outputs cell origin logical connection information with said cell as an origin; a signal origin logical connection information sampling part that receives said after-modification logical connection information and outputs signal origin logical connection information with a signal applied to said routing as an origin; a replacement cell determining part that receives said cell origin logical connection information and determines a replacement cell that should be replaced; and a rerouting signal determining part that receives said signal origin logical connection information and determines a rerouting signal that should be rerouted, wherein said replacement cell determining part makes a comparison, in cell units, between said after-modification logical connection information and said original logical connection information, and does not determine a comparison object cell as said replacement cell, if the sole difference is cell identification name, and said rerouting signal determining part makes a comparison, in signal units, between said after-modification logical connection information and said original logical connection information, and does not determine a comparison object signal as said rerouting signal, if the sole difference is signal name.