Pseudo document

(The real document is at https://nasm.us/doc/nasmdoc0.html

The definitions of Assembly language, Assembler and Netwide Assembler

⚠️ NOTE: It is recommended to learn how to program C language before programming this one, as I might use C syntax in order to perform the Netwide Assembler command for everyone to understand.

Establishment for Netwide Assembler language

Due to the high difficulty of installing this thing on Windows and MacOS, I will tell you how to do it on those platform later

Install Netwide Assembler compiler:

On Linux, Windows Subsystem for Linux or msys2:

For Ubuntu, Debian, Kali, Mint,...(Debian-based):

Update apt, then install nasm compiler:

sh Shell

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sudo apt update && sudo apt install nasm
For MSYS2, Arch Linux or Linux distro that uses pacman-package-manager (Arch-based):

Update pacman, then install nasm compiler:

sh Shell

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sudo pacman -Syu && sudo pacman --sync nasm
For Red Hat Linux or the Linux distro that uses yum package manager (RPM-based):

Update yum, then install nasm compiler:

sh Shell

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sudo yum -y update && sudo yum install nasm

Check off whether NASM is downloaded:

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nasm --version    #     It should output "NASM version <version>"
ndisasm -v        #  -- It should output "NDISASM version <version>"

Set up a new Intergrated Develop Environment in order to take down Netwide Assembler script easier

Please see my contents about Visual Studio Code, CoC and Neovim

Create your first Netwide Assembler source code

We will use Neovim for example to open a file. However, you can also open it using Vim or VS Code:

sh Shell

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nvim main.nasm

Then type:

Plaintext

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printHello

or ph, pH,...anything that relates to snippet printHello.

nvim-cmp will appear the snippet printHello for you.
It should output this script after choosing that snippet:

NASM

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%macro exit 1
  mov rax, 60
  mov rdi, %1
  syscall
%endmacro

%macro getstr 2
  mov rax, 1
  mov rdi, 1
  mov rsi, %1
  mov rdx, %2
  syscall
%endmacro

section .data
  example db 0x1b, "[1;38;2;255;165;0m", "Hello world", 0x1b, "[0m", 0xA
  length equ $-example

section .text
  global _start

_start:
  getstr example, length
  exit 0

Then use nasm to compile your Netwide Assembler file:

sh Shell

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nasm -f elf64 main.nasm -o main.o    # Compile NASM file into an object file using specified format
ld main.o -o main   # Link the object file to the binary, then make a binary file

Attention: You need to choose right format type in order to make the binary work.

According to nasm -hf instructions, we have some format like this:

Disassemble a RAW binary file (.bin, .hex) using ndisasm

Create an raw binary file. For instance: (ATTENTION: THIS IS THE COMMAND FOR x86-64 PROCESSOR MODE)

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echo -ne '\x48\xb8\x01\x00\x00\x00\x00\x00\x00\x00\x48\xbf\x01\x00\x00\x00\x00\x00\x00\x00\x48\xbe\x00\x10\x60\x00\x00\x00\x00\x00\x48\xba\x0c\x00\x00\x00\x00\x00\x00\x00\x0f\x05\x48\xb8\x3c\x00\x00\x00\x00\x00\x00\x00\x48\x31\xff\x0f\x05' > main.bin

Disassemble a RAW binary file (not real binary files like rm, cp, ls,...):

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ndisasm -b 64 main.bin    # You can use -b 16, 32, 64 if you want to use other preprocessors

If you use 64-bit preprocessor, it should output those texts like this (can be different from different processor modes).

ndisasm's Disassembly result

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00000000  48B8010000000000  mov rax,0x1
         -0000
0000000A  48BF010000000000  mov rdi,0x1
         -0000
00000014  48BE001060000000  mov rsi,0x601000
         -0000
0000001E  48BA0C0000000000  mov rdx,0xc
         -0000
00000028  0F05              syscall
0000002A  48B83C0000000000  mov rax,0x3c
         -0000
00000034  4831FF            xor rdi,rdi
00000037  0F05              syscall

Get started with Netwide Assembler

Not like mid-level and high-level programming languages, NASM is a low-level one and it is much harder to find documents for learning it. Moreover, before programming this language, you need to know some skills about basic things to deal with the CPU and compiler.

For more information about the nasm compiler, please go to the real document page.

NOTE AGAIN: I will assume you that you have known how to program C language. Therefore, you need to learn how to take down C script first.
However, don't worry if you have learnt many languages with the exeption of C. I also have an alternative one. This is the example clipboard that I will use:

C
Rust

Hello

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int main(void) {
  return 0;
}

1. Hexdecimal number and address

Hexdecimal is really important to deal with the data and initialize a value into things like:

Integer to Hexdecimal