Create a Function using $ASCII()

Hello,

I need to create a util function that loops thru every character in the data, execute a $ASCII() against it. If it falls outside the realm of extended ASCII we toss it.

the function should receive a string, execute a for...loop across it's length and use $ASCII to evaluate the character. Also the function should return an output argument that indicates if the string is UTF8 valid or not.

could anyone help me with this?