Assembly

• This repository is mainly about the x86 version of the Assembly language.
• Tutorial playlist: Intro to x86 Assembly Language (32-bit x86 Assembly)
• Find Syscalls and which registers to use
  • man 2 <syscall_name> can also be used to find the functions definition of the Syscall.

Compilation and Execution Instructions

# Use Netwide Assembler to compile assembly code to object file
$ nasm -f elf32 hello-world.asm -o hello-world.o

# Use GNU Linker to link object file and create an ELF (executable)
$ ld -m elf_i386 hello-world.o -o hello-world

# Execute the ELF
$ ./hello-world

Register Sizes

• 8-bit
  • AH, AL
• 16-bit
  • AX (AH:AL)
• 32-bit
  • EAX
• 64-bit
  • RAX

Data Sizes

• db or byte
  • One byte
• dw or word
  • One word, i.e., two bytes
• dd or dword
  • Double word, i.e., four bytes
• dq or qword
  • Quadruple word, i.e., eight bytes

Useful Commands

• file
• nm
• ldd
• objdump
• strace
• readelf
• gdb
• gf

Resources

• Assembly Language in 100 Seconds
• Intro to x86 Assembly Language (32-bit x86 Assembly)
• The faker's guide to reading (x86) assembly language
• Some Assembly Required
• x86 assembly doesn’t have to be scary (interactive)
• Web in Native Assembly (Linux x86_64)
• Brennan's Guide to Inline Assembly (AT&T vs Intel syntax)
• you can become a GALAXYBRAIN assembly programmers in 10 minutes
• godbolt.org
• Function calling in Assembly (Caller and Callee rules)
• Difference between .a, .s, .S and .asm
• Find Syscalls and which registers to use
• ASCII Table
• Is it possible to use 32 bits registers/instructions in real mode?
• In x86 what's difference between "test eax,eax" and "cmp eax,0"
• Netwide Assembler (NASM)
• NASM vs GAS