어셈블리[if]

-- var1.c --
#include <stdio.h>
int sum(int, int);     // sum 함수 선언

int main()
{
  int i = 3;
  int hap;
  hap = sum(i, 5);     // sum 함수 호출 
  printf("hap = %d \n", hap);
  return 0;
}
int sum(int a, int b)  // sum 함수 정의
{
  int res;
  res = a + b;
  return res;
}
-- var1.c --

-- 실행결과 --
# gcc -o var1-att.s -S var1.c
# gcc -o var1-att var1-att.s
# ./var1-att  
hap = 8 
-- 실행결과 --

-- var1-att.s --
.LC0:
	.string	"hap = %d \n"
.globl main
main:
	pushl	%ebp
	movl	%esp, %ebp
	subl	$16, %esp
	movl	$3, -8(%ebp)
	movl	$5, 4(%esp)
	movl	-8(%ebp), %eax
	movl	%eax, (%esp)
	call	sum
	movl	%eax, -4(%ebp)
	movl	-4(%ebp), %eax
	movl	%eax, 4(%esp)
	movl	$.LC0, (%esp)
	call	printf
	movl	$0, %eax
	leave
	ret
.globl sum
sum:
	pushl	%ebp
	movl	%esp, %ebp
	subl	$4, %esp
	movl	12(%ebp), %eax
	addl	8(%ebp), %eax
	movl	%eax, -4(%ebp)
	movl	-4(%ebp), %eax
	leave
	ret
-- var1-att.s --


-- if1.c --
#include <stdio.h>

int main()
{
  int i;
  i = 10;

  if(i == 10)
    printf("i = %d\n", i); 

  return 0;
}
-- if1.c --

-- ksw_if1.s --
.abc:
     .string "i = %d\n"

.globl main
main:
     pushl %ebp
     movl %esp, %ebp
     subl $12, %esp
     movl $10, -4(%ebp)
     cmpl $10, -4(%ebp)
     jne  .L2
     movl -4(%ebp), %eax
     movl %eax, -8(%ebp)
     #movl %eax, 4(%esp)
     movl $.abc, -12(%ebp)
     #movl $.abc, (%esp)
     call printf
.L2:
     movl $0, %eax
     leave
     ret
-- ksw_if1.s --

-- 실행결과 --
# gcc -o ksw_if1-att ksw_if1.s 
# ./ksw_if1-att 
i = 10
-- 실행결과 --

-- 소스분석 --
# gcc -g -o if1 if1.c 
# ./if1 
i = 10
# objdump -S if1 | grep -A 30 main.:
080483a4 <main>:
#include <stdio.h>

int main()
{
 80483a4:	55                   	push   %ebp
 80483a5:	89 e5                	mov    %esp,%ebp
 80483a7:	83 ec 0c             	sub    $0xc,%esp
  int i;
  i = 10;
 80483aa:	c7 45 fc 0a 00 00 00 	movl   $0xa,0xfffffffc(%ebp)

  if(i == 10)
 80483b1:	83 7d fc 0a          	cmpl   $0xa,0xfffffffc(%ebp)
 80483b5:	75 13                	jne    80483ca <main+0x26>
    printf("i = %d\n", i); 
 80483b7:	8b 45 fc             	mov    0xfffffffc(%ebp),%eax
 80483ba:	89 44 24 04          	mov    %eax,0x4(%esp)
 80483be:	c7 04 24 b0 84 04 08 	movl   $0x80484b0,(%esp)
 80483c5:	e8 ee fe ff ff       	call   80482b8 <printf@plt>

  return 0;
 80483ca:	b8 00 00 00 00       	mov    $0x0,%eax
}
 80483cf:	c9                   	leave  
 80483d0:	c3                   	ret 
-- 소스분석 --