Lab 5B: Loop program (X86-64)

A. Introduction:

In this lab, we will begin to use assembly language for architecture AArch64 and x86-64
To view the code for AArch64, please visit this pastebin link
Before you go on, I must say that this is similar to the AArch64 version. The only difference is where the remainder and quotient are stored in the memory

In assembly, there are different sections that serve a sole purpose. For example, the text section is used to store your code while the data and bss sections are used to declare variables
In the text section, there is a _start label that declare the start of the program

First, we need to have the maximum of loops we want to perform or it will be an infinite loop. For this program, we will be using 2 constants for the minimum and maximum loop. However, these are not variables, they are just constants
In the data section, we have 2 variables to store the message and the length of the message

As the index increasing, we need to check whether the index is single or double digit before we display it
To do so, we need to find the quotient and remainder by divide the index with 10
The remainder will be the digit on the right while the quotient will be the digit on the left
However, the quotient is stored in the ‘al’ register while the remainder is stored in the ‘dx’ register
Then, we check if the quotient is0 or not. If the quotient is 0 then the index only has one digit
Finally, after the digit are checked out, we will load them into the position after the “Loop: ” message

To print the message, we need to use specific values for the system call
The values including the address of the message, the length of the message, which operation and stream to use
In this case, the operation will be writing and the stream will be standard output