[참고]어셈블리 예제

 

[EX] sample.c (C 언어 작성) --- 변환 --> sample.a (어셈블리어)

 

$ cd

$ cd tmp

$ vi sample.c

int function(int a, int b){                 char buffer[10];                 a = a + b;                 return a; }   int main(void){                 int c;                 c = function(1,2);                 return 0; }

$ gcc -S -o sample.a sample.c

$ ls -l

-rw-rw-r-- 1 level1 level1 570 11월 25 12:17 sample.a -rw-rw-r-- 1 level1 level1 131 11월 25 12:16 sample.c

 

$ file *

sample.a: ASCII assembler program text sample.c: ASCII C program text

 

$ vi sample.a

.file   "sample.c"         .text .globl function         .type   function,@function function:         pushl   %ebp         movl    %esp, %ebp         subl    $24, %esp         movl    12(%ebp), %eax         addl    %eax, 8(%ebp)         movl    8(%ebp), %eax         leave         ret .Lfe1:         .size   function,.Lfe1-function .globl main         .type   main,@function main:         pushl   %ebp         movl    %esp, %ebp         subl    $8, %esp         andl    $-16, %esp         movl    $0, %eax         subl    %eax, %esp         subl    $8, %esp         pushl   $2         pushl   $1         call    function         addl    $16, %esp         movl    %eax, -4(%ebp)         movl    $0, %eax         leave         ret .Lfe2:         .size   main,.Lfe2-main         .ident  "GCC: (GNU) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)"

 

 

[EX2] sample.c (C 언어) -----> sample (바이너리) -----> disassemble (어셈블리어)

$ gcc -o sample sample.c

$ file sample*

sample: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.5, dynamically linked (uses shared libs), not stripped sample.a: ASCII assembler program text sample.c: ASCII C program text

 

$ gdb -q sample

(gdb) disassemble main Dump of assembler code for function main: 0x08048305  <main+0>:  push  %ebp 0x08048306  <main+1>:  mov   %esp,%ebp 0x08048308  <main+3>:  sub   $0x8,%esp 0x0804830b  <main+6>:  and   $0xfffffff0,%esp 0x0804830e  <main+9>:  mov   $0x0,%eax 0x08048313  <main+14>: sub   %eax,%esp 0x08048315  <main+16>: sub   $0x8,%esp 0x08048318  <main+19>: push  $0x2 0x0804831a  <main+21>: push  $0x1 0x0804831c  <main+23>: call  0x80482f4 <function> 0x08048321  <main+28>: add   $0x10,%esp 0x08048324  <main+31>: mov   %eax,0xfffffffc(%ebp) 0x08048327  <main+34>: mov   $0x0,%eax 0x0804832c  <main+39>: leave 0x0804832d  <main+40>: ret 0x0804832e  <main+41>: nop 0x0804832f  <main+42>: nop End of assembler dump.

 

 

 

(정리)

sample.c (C 언어) -----> sample.a (어셈블리어)

sample.c (C 언어) -----> sample (바이너리) ----- gdb ----> disassemble (어셈블리어)