# Code Implementation
## subtraction, multiplication
Just straight forward use 'sub' 'mult'

## division
First, check whether denominator is zero. If it is zero, go to 'ret', else go to 'result'

## itoa function
Iteratively divide input integer, convert remainder to string by adding '0' ascii number and store the ascii code directly into 'output_ascii' array.

# Environment
Windows 10 64bit