In the last post, I showed some code that had a very simple problem.
The problem is that when you call HIWORD, it converts the 16 bits into an unsigned short, which then gets passed as an int padded with zeros–not sign extended (it’s not signed). It will NEVER be less than zero. The solution is to cast it to a signed short before calling the function or change the function parameters to be signed short instead of int.
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