Method and apparatus for patching code residing on a read only memory device

摘要

A method and apparatus for generating patching resources in an information processing system having operating instructions on a Read Only Memory Device. The present invention simplifies the patch generation and installation processes. A patch resource is generated and used by a patch installation process. Patch resources are generated for each ROM version by comparing previous ROM versions to the new ROM version. A patch resource is comprised of a plurality of entries, each of which defines a vector table address, an offset into the vector table and the routine to be inserted. By comparing routines between the ROM versions, routines which are different or new are identified. These routines will become patch resource entries. For patch installation, the ROM version number for the installed ROM is determined; the proper patching resource is retrieved, and the patch resource entries cause the patches to be installed. Patch installation is performed by the steps of modifying vector tables to include the addresses for the new routines.