1.8 KiB
libasm
Why I did this project
I wanted to do this project for a while because I am interested in low level programming and assembly seemed very interesting. I had a lot of fun doing it, learning about function calling conventions, x86_64 architecture and other things.
How to compile it
To compile the project, you'll need nasm and make. Optionally, if you want to compile the tests,
you will need clang.
Once you have these requirements, simply run the command make and the project should compile.
The result is a library that you can add to your project with -L<folder> -lasm, folder being the folder where the file libasm.a is located
test the project
for every function asked for by the subject, there is a testing function in the file test.c
To compile the tests run the command make tests. Then run the resulting executable with ./test
Useful documentation
While doing this project, since I had never programmed in x86_64 assembly before, I had to find some basic documentation.
I mostly had trouble with remembering the order of the functions parameters in the registers, I kept going back to
this stackoverflow thread
provided the order I needed. And in this thread I found information about the System V calling convention.
The order I needed was : rdi, rsi, rdx, rcx, r8, r9
During this project, I also needed to make system calls. To their parameters and numbers, I used this page which has a table of all the system calls.
Finally I also used this website to find more info about some instructions I didn't understand. It was also a useful resource for finding the appropriate jump instructions based on my needs.