Yeah I've searched everywhere. I don't think I'd be able to find the definition of that function, because it would be in hl.exe, the engine file. Not that I need to use that. I could just as easily replace the function call with a constant value, but fussy as I am, I have to work out what's happening.

Do you thing it's possible that the actual constants are stored in hl.exe? It seems unlikely to me because that would reduce the ability to quickly modify the game constants.