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@netom
Created March 26, 2021 13:12
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Tiny "Hello World" program for Linux (>=2.2)
; Credits: https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
; Compile: nasm -f bin -o hello hello.asm
BITS 32
org 0x08048000
ehdr: ; Elf32_Ehdr
db 0x7F, "ELF", 1, 1, 1, 0 ; e_ident
times 8 db 0
dw 2 ; e_type
dw 3 ; e_machine
dd 1 ; e_version
dd _start ; e_entry
dd phdr - $$ ; e_phoff
dd 0 ; e_shoff
dd 0 ; e_flags
dw ehdrsize ; e_ehsize
dw phdrsize ; e_phentsize
dw 1 ; e_phnum
dw 0 ; e_shentsize
dw 0 ; e_shnum
dw 0 ; e_shstrndx
ehdrsize equ $ - ehdr
phdr: ; Elf32_Phdr
dd 1 ; p_type
dd 0 ; p_offset
dd $$ ; p_vaddr
dd $$ ; p_paddr
dd filesize ; p_filesz
dd filesize ; p_memsz
dd 5 ; p_flags
dd 0x1000 ; p_align
phdrsize equ $ - phdr
_start:
mov al, 4 ; sys_write(
mov bl, 0 ; unsigned int,
mov ecx, hello ; const char *,
mov dl, 13 ; size_t
int 0x80 ; )
xor eax, eax ; sys_exit(
inc eax ; int // notice that ebx is still 0
int 0x80 ; )
hello: db `Hello World!\n`
filesize equ $ - $$
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