Assembly Programming Language Cheatsheet

Assembly language is a low-level programming language that is closely tied to the architecture of a computer’s central processing unit (CPU). It is a symbolic representation of machine code, allowing programmers to write code that is more readable than machine code but still closely related to the hardware. Assembler is the tool used to convert assembly language code into machine code. This cheatsheet serves as a quick reference guide for those diving into the world of assembly programming.

1. Basic Structure

section .data
    ; Data segment - declare variables

section .text
    global _start
    ; Code segment - start of the program

_start:
    ; Main entry point
    ; Program instructions go here

section .bss
    ; Uninitialized data segment - reserve space for variables

2. Registers

; General-purpose registers
eax, ebx, ecx, edx

; Index registers
esi, edi

; Base pointer and stack pointer
ebp, esp

; Flags register
eflags

3. Data Movement

mov destination, source   ; Move data from source to destination

4. Arithmetic and Logic

add destination, source   ; Add source to destination
sub destination, source   ; Subtract source from destination
mul source                ; Multiply destination by source
div source                ; Divide destination by source
and destination, source   ; Bitwise AND
or destination, source    ; Bitwise OR
xor destination, source   ; Bitwise XOR

5. Control Flow

jmp label          ; Jump to label unconditionally
je label           ; Jump if equal (ZF=1)
jne label          ; Jump if not equal (ZF=0)
jl label           ; Jump if less than (SF ≠ OF)
jg label           ; Jump if greater than (ZF=0 and SF=OF)
call subroutine    ; Call a subroutine
ret                ; Return from subroutine

6. Stack Operations

push value         ; Push value onto the stack
pop destination    ; Pop value from the stack into destination

7. Procedure Declaration

section .text
global my_function   ; Declare a global function

my_function:
    ; Function code goes here
    ret

8. Input/Output

section .data
    output db 'Hello, World!', 0

section .text
    ; Output to console
    mov eax, 4            ; Syscall number for sys_write
    mov ebx, 1            ; File descriptor (1 for stdout)
    mov ecx, output       ; Pointer to the message
    mov edx, 13           ; Length of the message
    int 0x80              ; Call kernel

    ; Exit program
    mov eax, 1            ; Syscall number for sys_exit
    xor ebx, ebx          ; Exit code 0
    int 0x80              ; Call kernel

9. Macros

%macro my_macro 2
    ; Macro code with %1 and %2 as parameters
%endmacro

10. System Calls

section .text
    mov eax, 4       ; Syscall number for sys_write
    mov ebx, 1       ; File descriptor (1 for stdout)
    mov ecx, message ; Pointer to the message
    mov edx, length  ; Length of the message
    int 0x80         ; Call kernel

This cheatsheet provides a glimpse into the essential aspects of assembly language programming. As you delve deeper into the world of assembly, you’ll discover its power and efficiency in working closely with hardware, making it a valuable skill for low-level programming and optimization tasks.

Refer to the official documentation for more in-depth information and examples.

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