FAQ-0431 How do I find the address of a ROM entry point?


FAQ-0431 How do I find the address of a ROM entry point?

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Classification:	C++	Category:	Base
Created:	11/11/99	Modified:	12/11/2001
Number:	FAQ-0431
Platform:	ER5

Question:
I need to patch a function - let's say it's RFile::Open(). However each new ROM build has a different address for the function. What can I do about it?

Answer:
There is an algorithmic method for finding the address of RFile::Open on any ROM.

The export RFile::Open() has a constant Ordinal in EFSRV.DLL (105), so if you scan the Rom Directory structure for EFSRV.DLL you can get the TRomImageHeader for this Dll. The TRomImageHeader contains a pointer to the export directory, and the 105th entry is the address of RFile::Open.