Assembly Basics

; Data movement mov rax, 42 ; load immediate mov rbx, rax ; register to register mov [rsp], rax ; store to memory push rbx ; push to stack pop rbx ; pop from stack ; Arithmetic add rax, rbx ; rax = rax + rbx sub rax, 10 ; rax = rax - 10 imul rax, 3 ; rax = rax * 3 idiv rcx ; rax = rax / rcx, rdx = remainder inc rax ; rax++ dec rax ; rax-- ; Logical and rax, rbx ; bitwise AND or rax, rbx ; bitwise OR xor rax, rax ; zero rax not rax ; bitwise NOT shl rax, 2 ; left shift shr rax, 1 ; right shift

section .data msg db "Hello, World!", 10 len equ $ - msg section .text global _start _start: mov rax, 1 ; sys_write mov rdi, 1 ; stdout mov rsi, msg ; buffer mov rdx, len ; length syscall mov rax, 60 ; sys_exit xor rdi, rdi ; exit code 0 syscall