Write basic procedure in MIPS using MARS simulator

Write a MIPS procedure called findx which finds the first occurrence of the letter x in an area of memory (array). The procedure receives three arguments in $a1, $a2, and $a3, where $a1 is the starting memory address of a null-terminated ASCII string, $a2 has the starting index (0) and $a3 is the x character. The findx procedure will locate the first x character in the string and return the position where it was found in register $v1. If there are no xes in the string, findx should return -1 in register $v1. Your program should print the index returned by findx using a syscall. Make sure to write plenty of comments so that your code is as easy to understand. Thank you for your help!