$[02]$ Write a function with the following specifications:

Name: fun.

Input: define as needed.

Output: define as needed.

Process: finds and returns the frequency $($number of occurrences$)$ of a character in a string.

Conditions: must NOT use stack frame to pass parameters.

$($Code must be written in x$86-$ MASM assembler and use only irvine and macros libraries$)$