iic.c(14): warning C206: '_nop_': missing function-prototype

This warning is related to the use of the `_nop_` function in the code. The `_nop_` function is used to insert a no-operation instruction in the code. However, since this function is not defined in the standard C library, the compiler does not know its signature and cannot verify if it is used correctly.

To fix this warning, you can include the appropriate header file that defines the `_nop_` function or write your own function that performs a no-operation instruction. Alternatively, you can disable the warning by adding a pragma directive to your code:

#pragma warning(disable:206)

However, it is generally not recommended to disable warnings as they can help identify potential issues in the code.