先搭配好环境
sudo apt-get install nasm
创建一个asm文件
section .data
text db "Hello World", 10
section .text
global _start
_start:
mov rax, 1
mov rdi, 1
mov rsi, text
mov rdx, 14
syscall
mov rax, 60
mov rdi, 0
syscall
nasm生成对象文件
nasm -f elf64 -o one.o one.asm
链接生成可执行文件
ld one.o -o one
执行文件
➜ asm ./one
Hello World
查看文件信息
➜ asm file one
one: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped
➜ asm objdump -d one
one: file format elf64-x86-64
Disassembly of section .text:
0000000000401000 <_start>:
401000: b8 01 00 00 00 mov $0x1,%eax
401005: bf 01 00 00 00 mov $0x1,%edi
40100a: 48 be 00 20 40 00 00 movabs $0x402000,%rsi
401011: 00 00 00
401014: ba 0e 00 00 00 mov $0xe,%edx
401019: 0f 05 syscall
40101b: b8 3c 00 00 00 mov $0x3c,%eax
401020: bf 00 00 00 00 mov $0x0,%edi
401025: 0f 05 syscall
可知其为可执行文件（executable）
来看看具体的文件架构
➜ C readelf -a ../asm/one
ELF Header:
Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: Advanced Micro Devices X86-64
Version: 0x1
Entry point address: 0x401000
Start of program headers: 64 (bytes into file)
Start of section headers: 8504 (bytes into file)
Flags: 0x0
Size of this header: 64 (bytes)
Size of program headers: 56 (bytes)
Number of program headers: 3
Size of section headers: 64 (bytes)
Number of section headers: 6
Section header string table index: 5
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .text PROGBITS 0000000000401000 00001000
0000000000000027 0000000000000000 AX 0 0 16
[ 2] .data PROGBITS 0000000000402000 00002000
000000000000000c 0000000000000000 WA 0 0 4
[ 3] .symtab SYMTAB 0000000000000000 00002010
00000000000000d8 0000000000000018 4 5 8
[ 4] .strtab STRTAB 0000000000000000 000020e8
0000000000000026 0000000000000000 0 0 1
[ 5] .shstrtab STRTAB 0000000000000000 0000210e
0000000000000027 0000000000000000 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
l (large), p (processor specific)
There are no section groups in this file.
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000
0x00000000000000e8 0x00000000000000e8 R 0x1000
LOAD 0x0000000000001000 0x0000000000401000 0x0000000000401000
0x0000000000000027 0x0000000000000027 R E 0x1000
LOAD 0x0000000000002000 0x0000000000402000 0x0000000000402000
0x000000000000000c 0x000000000000000c RW 0x1000
Section to Segment mapping:
Segment Sections...
00
01 .text
02 .data
There is no dynamic section in this file.
There are no relocations in this file.
The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.
Symbol table '.symtab' contains 9 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000401000 0 SECTION LOCAL DEFAULT 1
2: 0000000000402000 0 SECTION LOCAL DEFAULT 2
3: 0000000000000000 0 FILE LOCAL DEFAULT ABS one.asm
4: 0000000000402000 0 NOTYPE LOCAL DEFAULT 2 text
5: 0000000000401000 0 NOTYPE GLOBAL DEFAULT 1 _start
6: 000000000040200c 0 NOTYPE GLOBAL DEFAULT 2 __bss_start
7: 000000000040200c 0 NOTYPE GLOBAL DEFAULT 2 _edata
8: 0000000000402010 0 NOTYPE GLOBAL DEFAULT 2 _end
No version information found in this file.
慢慢来吧！
