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06/28/2023 |
This is the lowest level programming language possible. It is also rather simple once you get the hang of it.
It was originally created in the 40's to prevent computer scientists from having to manually count binary on their hands.
Keep in mind that each assembly language only works on specific chips.
- ARM for Apple Silicon
- x86 for Intel
First, you will need an assembler.
{% embed url="https://www.nasm.us/" %}
Use masm if you plan on using Windows. However, for asm, I do not recommend using Windows. I feel like it is way easier to understand on a Unix platform syntactically. Unfortunately, the rest of this article is not for you if you plan on going the Windows route.
sudo apt install as31 nasm
sudo apt install gdb gcc binutils
Press CTRL + P in VS Code and install the following:
ext install DamianKoper.gdb-debug
ext install maziac.asm-code-lens
You are now ready to begin development in asm with VS Code!
The program is divided into three sections.
- Text section: main program code -- all of the logic -- How do you want your program to do it?
- Block Starting Symbol section: variables
- Data section: contains all of the strings and other data you want to do in here. What do you want your program to do?
helloWorld.asm:
section .text
global _start
_start:
mov edx,len
mov ecx,msg
mov ebx,1
mov eax,4
int 0x80
mov eax,1
int 0x80
section .data
msg db 'Hello world!!!!!!',0xa
len equ $ - msg
Also, the len has no maximum length. I tried to overflow it with a TON of A's, but since msg takes len as its length, it is all statically allocated and handles the long string. -- I think this is true. Please check me on this.
nasm -f elf64 helloWorld.asm
This will generate a helloWorld.o.
ld -s -o helloWorld helloWorld.o
./helloWorld
Hello world!!!!!!
{% embed url="https://blog.rchapman.org/posts/Linux_System_Call_Table_for_x86_64/" %}