My test harness loads up the original DLL then executes that in parallel against the converted code (differential testing). That closes the feedback loop the LLM needs to be able to find and fix discrepancies.
I'm also doing this on an old Win32 DLL so the task is probably much easier than a lot of code bases.
I'm also doing this on an old Win32 DLL so the task is probably much easier than a lot of code bases.