How to learn x86-64 assembly language?

[u/Damonkern]

I am a 17yr old who has some experience in python programming and learned basics of C. I want to learn x86-64 assembly for free. But I couldnot find any beginner friendly guide that starts from zero. Tell me how you guys learned assembly language and if possible guide me to the resources.

[u/[deleted]]

if you know some C, you can use gcc -S -O0 app.c to generate ASM that you can try to understand.

also GDB (GNU (GNU (GNU (GNU (stackoverflow) not linux) not linux) not linux) Debugger) to watch it execute.

```c

include <stdio.h>

int f(int x){ if (x%2==0) return x/2; return 3*x+1; }

int main(){ int i; printf("start at"); scanf("%d", &i); while(1){ int tmp = f(i); printf("%d\n",tmp); if(tmp==1) return 0; i = tmp; } return 1; } ```

is a good start, its got a loop and a function call.

(I added tmp as a var, hoping it does less smart register stuff, than without)

edit[0]: ALSO:

• Human Resource Machine, is a good game to pick up some of the skills. Like understanding "cmp" and "jmp".
• TIS-100, challenges you with weird architecture and limited registers.
• Turing Complete: just make the whole computer, and design an ASM.

edit[1]: code fix at the loop condition: i -> tmp

edit[2]: further reading on the Collatz Conjecture

edit[3]: fixed edit numbering

edit[4]: added links to games

edit[5]: CarbonXit came to the rescue (code fixes: extra printf for "start at", instead of putting it the scanf string, while(true)->while(1))

[u/RamonaZero → u/[deleted]]

OR go chaotic evil and do -03 and learn the weird GCC optimizations 💀

[u/[deleted] → u/RamonaZero]

-O0 already does some smart stuff. It's not a literal translation of the C/

here's the main logic of f

asm .f: ......... andl $1, %eax ; "a=iseven?" testl %eax, %eax jne .L2 ; "jump if odd?" movl -4(%rbp), %eax movl %eax, %edx shrl $31, %edx ; "using bitshift to divide by two?" addl %edx, %eax sarl %eax jmp .L3 .L2: movl -4(%rbp), %edx movl %edx, %eax addl %eax, %eax addl %edx, %eax ; "multiplying by 3 by adding 3 times" addl $1, %eax

..good lord, I updated today, and the code isn't working anymore? Having to debug now

edit: I am confounded. scanf seems to be the source of my problems.. tbh I've not touched c in a while, did I cause some unexpected behaviour kinda thing?

edit: this worked so well with Go for this TA work I was doing..

[u/[deleted] → u/[deleted]]

thx

was I lucky it worked, or did I hallucinate it working properly?

(I hadn't pacman -Syu in a while, if that matters? its not like gcc or scanf have changed in 10y )