我正在理解汇编和 C 代码。我有以下 C 程序,编译为仅生成对象文件。
#include <stdio.h>
int main()
{
int i = 10;
int j = 22 + i;
return 0;
}
我执行了以下命令
objdump -S myprogram.o
上述命令的输出为:
objdump -S testelf.o
testelf.o: file format elf32-i386
Disassembly of section .text:
00000000 <main>:
#include <stdio.h>
int main()
{
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 83 ec 10 sub $0x10,%esp
int i = 10;
6: c7 45 f8 0a 00 00 00 movl $0xa,-0x8(%ebp)
int j = 22 + i;
d: 8b 45 f8 mov -0x8(%ebp),%eax
10: 83 c0 16 add $0x16,%eax
13: 89 45 fc mov %eax,-0x4(%ebp)
return 0;
16: b8 00 00 00 00 mov $0x0,%eax
}
1b: c9 leave
1c: c3 ret
助记命令之前的数字是什么意思,即“sub”命令之前的“83 ec 10”或“movl”命令之前的“c7 45 f8 0a 00 00 00”
我正在使用以下平台来编译此代码:
$ lscpu
Architecture: i686
CPU op-mode(s): 32-bit
Byte Order: Little Endian
CPU(s): 1
On-line CPU(s) list: 0
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 1
Vendor ID: GenuineIntel