https://github.com/rodolfobandeira/assembly-linux-studies

https://github.com/rodolfobandeira/assembly-linux-studies

assembly nasm ubuntu

Last synced: 14 days ago
JSON representation

• Host: GitHub
• URL: https://github.com/rodolfobandeira/assembly-linux-studies
• Owner: rodolfobandeira
• Created: 2016-07-11T01:25:43.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-12-08T02:30:38.000Z (about 7 years ago)
• Last Synced: 2024-12-18T12:12:00.323Z (about 2 months ago)
• Topics: assembly, nasm, ubuntu
• Language: Assembly
• Size: 3.91 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
#### Assembly Linux Studies (64 bits arquitecture)

`nasm -f elf64 -o nasm_64_bits_hello_world.o nasm_64_bits_hello_world.asm`

`ld -o nasm_64_bits_hello_world nasm_64_bits_hello_world.o`

```

section .data

    msg db 'Rodolfo Bandeira', 0xA  ; our string

    len equ $ - msg                 ; length of our string

section .text

    global _start

; -----------------------------------------

; 64 bit registers:

; -----------------------------------------

; rax, rbx, rcx, rdx,

; rsi, rdi,

; rsp,

; r8, r9, r10, r11, r12, r13, r14, r15, r16

; -----------------------------------------

;

; We're going to use the system call bellow:

; ssize_t sys_write(unsigned int fd, const char * buf, size_t count)

;

; This is the registers used for the parameters

; -------------------------------------------------------------------------------

; System Call    |          rdi        |         rsi         |        rdx       |

; -------------------------------------------------------------------------------

; sys_write (1)  |   unsigned int fd   |   const char *buf   |   size_t count   |

; sys_exit (60)  |   int error_code    |                     |                  |

; -------------------------------------------------------------------------------

_start:

    mov     rax, 0x01              ; system call number (sys_write)

    mov     rdi, 0x01              ; file descriptor

    mov     rsi, msg               ; message

    mov     rdx, len               ; message length

    syscall                        ; call kernel

    mov     rax, 0x3C              ; system call (sys_exit) 60 = 0x3C

    mov     rdi, 0x00              ; 0 means no error

    syscall                        ; call kernel

; To compile:

;

; nasm -f elf64 -o nasm_64_bits_hello_world.o nasm_64_bits_hello_world.asm

; ld -o nasm_64_bits_hello_world nasm_64_bits_hello_world.o

; ./nasm_64_bits_hello_world

```

#### Reference:

- http://0xax.blogspot.ca/2014/08/say-hello-to-x64-assembly-part-1.html

- Free Assembly 64 bits + Ubuntu E-book: http://www.egr.unlv.edu/~ed/x86.html