1 栈和过程调用
```00000000 <swap>:0: 55 push %ebp1: 89 e5 mov %esp,%ebp3: 83 ec 10 sub $0x10,%esp6: 8b 45 08 mov 0x8(%ebp),%eax9: 8b 00 mov (%eax),%eaxb: 89 45 fc mov %eax,-0x4(%ebp)e: 8b 45 0c mov 0xc(%ebp),%eax11: 8b 10 mov (%eax),%edx13: 8b 45 08 mov 0x8(%ebp),%eax16: 89 10 mov %edx,(%eax)18: 8b 45 0c mov 0xc(%ebp),%eax1b: 8b 55 fc mov -0x4(%ebp),%edx1e: 89 10 mov %edx,(%eax)20: c9 leave 21: c3 ret 详解：
```00000000 <swap>:0: 55 push %ebp1: 89 e5 mov %esp,%ebp3: 83 ec 10 sub $0x10,%esp //分配16字节空间（10进制6: 8b 45 08 mov 0x8(%ebp),%eax //M[0x8(%ebp)]的参数移到%eax9: 8b 00 mov (%eax),%eax //将%eax指向的内存地址移到寄存器%eaxb: 89 45 fc mov %eax,-0x4(%ebp) //将%eax的值赋给基址-0x4(%ebp)e: 8b 45 0c mov 0xc(%ebp),%eax //M[0xc(%ebp)]的参数移到%eax11: 8b 10 mov (%eax),%edx13: 8b 45 08 mov 0x8(%ebp),%eax16: 89 10 mov %edx,(%eax) //将%edx指向的值移到%eax指向的内存地址18: 8b 45 0c mov 0xc(%ebp),%eax //1b: 8b 55 fc mov -0x4(%ebp),%edx //1e: 89 10 mov %edx,(%eax) //将%edx指向的值移到%eax指向的内存地址20: c9 leave21: c3 ret
C语言代码参考
int swap(int *x,int*y){
//**********Begin**********int t;t=*x;*x=*y;*y=t;//**********End**********
} 2 条件/选择结构分析
2.1 if else条件选择结构
08049172 <main>:8049172: 8d 4c 24 04 lea 0x4(%esp),%ecx8049176: 83 e4 f0 and $0xfffffff0,%esp8049179: ff 71 fc pushl -0x4(%ecx)804917c: 55 push %ebp804917d: 89 e5 mov %esp,%ebp804917f: 51 push %ecx8049180: 83 ec 14 sub $0x14,%esp8049183: 83 ec 04 sub $0x4,%esp8049186: 8d 45 f0 lea -0x10(%ebp),%eax8049189: 50 push %eax804918a: 8d 45 f4 lea -0xc(%ebp),%eax804918d: 50 push %eax804918e: 68 08 a0 04 08 push $0x804a0088049193: e8 b8 fe ff ff call 8049050 <__isoc99_scanf@plt>8049198: 83 c4 10 add $0x10,%esp804919b: 8b 55 f4 mov -0xc(%ebp),%edx804919e: 8b 45 f0 mov -0x10(%ebp),%eax80491a1: 39 c2 cmp %eax,%edx80491a3: 7e 18 jle 80491bd <main+0x4b>80491a5: 8b 55 f0 mov -0x10(%ebp),%edx80491a8: 8b 45 f4 mov -0xc(%ebp),%eax80491ab: 83 ec 04 sub $0x4,%esp80491ae: 52 push %edx80491af: 50 push %eax80491b0: 68 0d a0 04 08 push $0x804a00d80491b5: e8 76 fe ff ff call 8049030 <printf@plt>80491ba: 83 c4 10 add $0x10,%esp80491bd: 8b 55 f4 mov -0xc(%ebp),%edx80491c0: 8b 45 f0 mov -0x10(%ebp),%eax80491c3: 39 c2 cmp %eax,%edx80491c5: 75 1a jne 80491e1 <main+0x6f>80491c7: 8b 55 f0 mov -0x10(%ebp),%edx80491ca: 8b 45 f4 mov -0xc(%ebp),%eax80491cd: 83 ec 04 sub $0x4,%esp80491d0: 52 push %edx80491d1: 50 push %eax80491d2: 68 15 a0 04 08 push $0x804a01580491d7: e8 54 fe ff ff call 8049030 <printf@plt>80491dc: 83 c4 10 add $0x10,%esp80491df: eb 18 jmp 80491f9 <main+0x87>80491e1: 8b 55 f0 mov -0x10(%ebp),%edx80491e4: 8b 45 f4 mov -0xc(%ebp),%eax80491e7: 83 ec 04 sub $0x4,%esp80491ea: 52 push %edx80491eb: 50 push %eax80491ec: 68 1d a0 04 08 push $0x804a01d80491f1: e8 3a fe ff ff call 8049030 <printf@plt>80491f6: 83 c4 10 add $0x10,%esp80491f9: b8 00 00 00 00 mov $0x0,%eax80491fe: 8b 4d fc mov -0x4(%ebp),%ecx8049201: c9 leave8049202: 8d 61 fc lea -0x4(%ecx),%esp8049205: c3 ret详解：
08049172 <main>:8049172: 8d 4c 24 04 lea 0x4(%esp),%ecx8049176: 83 e4 f0 and $0xfffffff0,%esp //16字节对齐8049179: ff 71 fc pushl -0x4(%ecx)804917c: 55 push %ebp804917d: 89 e5 mov %esp,%ebp804917f: 51 push %ecx //把%ecx压入栈8049180: 83 ec 14 sub $0x14,%esp8049183: 83 ec 04 sub $0x4,%esp8049186: 8d 45 f0 lea -0x10(%ebp),%eax //8049189: 50 push %eax804918a: 8d 45 f4 lea -0xc(%ebp),%eax804918d: 50 push %eax804918e: 68 08 a0 04 08 push $0x804a0088049193: e8 b8 fe ff ff call 8049050 <__isoc99_scanf@plt> //调用scanf8049198: 83 c4 10 add $0x10,%esp //回收栈上的空间804919b: 8b 55 f4 mov -0xc(%ebp),%edx // 内存的值赋给%edx804919e: 8b 45 f0 mov -0x10(%ebp),%eax // 内存的值赋给%eax80491a1: 39 c2 cmp %eax,%edx //比较eax与edx80491a3: 7e 18 jle 80491bd <main+0x4b> //小于就跳转到80491bd80491a5: 8b 55 f0 mov -0x10(%ebp),%edx80491a8: 8b 45 f4 mov -0xc(%ebp),%eax80491ab: 83 ec 04 sub $0x4,%esp80491ae: 52 push %edx80491af: 50 push %eax80491b0: 68 0d a0 04 08 push $0x804a00d80491b5: e8 76 fe ff ff call 8049030 <printf@plt>80491ba: 83 c4 10 add $0x10,%esp80491bd: 8b 55 f4 mov -0xc(%ebp),%edx80491c0: 8b 45 f0 mov -0x10(%ebp),%eax80491c3: 39 c2 cmp %eax,%edx80491c5: 75 1a jne 80491e1 <main+0x6f> //不相等就跳转80491e180491c7: 8b 55 f0 mov -0x10(%ebp),%edx80491ca: 8b 45 f4 mov -0xc(%ebp),%eax80491cd: 83 ec 04 sub $0x4,%esp80491d0: 52 push %edx80491d1: 50 push %eax80491d2: 68 15 a0 04 08 push $0x804a01580491d7: e8 54 fe ff ff call 8049030 <printf@plt>80491dc: 83 c4 10 add $0x10,%esp80491df: eb 18 jmp 80491f9 <main+0x87>80491e1: 8b 55 f0 mov -0x10(%ebp),%edx80491e4: 8b 45 f4 mov -0xc(%ebp),%eax80491e7: 83 ec 04 sub $0x4,%esp80491ea: 52 push %edx80491eb: 50 push %eax80491ec: 68 1d a0 04 08 push $0x804a01d80491f1: e8 3a fe ff ff call 8049030 <printf@plt>80491f6: 83 c4 10 add $0x10,%esp80491f9: b8 00 00 00 00 mov $0x0,%eax80491fe: 8b 4d fc mov -0x4(%ebp),%ecx8049201: c9 leave8049202: 8d 61 fc lea -0x4(%ecx),%esp8049205: c3 ret
C语言代码参考
#include <stdio.h>
int main()
{int a, b;scanf("%d%d", &a, &b);printf("评测结果：成功\n评测脚本：C\n返回结果：");//此行不在汇编代码中//**********Begin**********if(a>b)//**********End************ printf("%d > %d", a, b);//**********Begin**********if(a==b)//**********End************ printf("%d = %d", a, b);//**********Begin**********if(a<b)//**********End************printf("%d < %d", a, b);return 0;
}
2.2 switch选择结构
08049182 <main>:8049182: 8d 4c 24 04 lea 0x4(%esp),%ecx8049186: 83 e4 f0 and $0xfffffff0,%esp8049189: ff 71 fc pushl -0x4(%ecx)804918c: 55 push %ebp804918d: 89 e5 mov %esp,%ebp804918f: 51 push %ecx8049190: 83 ec 14 sub $0x14,%esp8049193: 83 ec 08 sub $0x8,%esp8049196: 8d 45 f4 lea -0xc(%ebp),%eax8049199: 50 push %eax804919a: 68 08 a0 04 08 push $0x804a008804919f: e8 bc fe ff ff call 8049060 <__isoc99_scanf@plt>80491a4: 83 c4 10 add $0x10,%esp80491a7: 83 ec 0c sub $0xc,%esp80491aa: 68 0c a0 04 08 push $0x804a00c80491af: e8 7c fe ff ff call 8049030 <printf@plt>80491b4: 83 c4 10 add $0x10,%esp80491b7: 8b 45 f4 mov -0xc(%ebp),%eax80491ba: 83 f8 06 cmp $0x6,%eax80491bd: 77 73 ja 8049232 <main+0xb0>80491bf: 8b 04 85 54 a0 04 08 mov 0x804a054(,%eax,4),%eax80491c6: ff e0 jmp *%eax80491c8: 83 ec 0c sub $0xc,%esp80491cb: 68 43 a0 04 08 push $0x804a04380491d0: e8 6b fe ff ff call 8049040 <puts@plt>80491d5: 83 c4 10 add $0x10,%esp80491d8: eb 69 jmp 8049243 <main+0xc1>80491da: 83 ec 0c sub $0xc,%esp80491dd: 68 45 a0 04 08 push $0x804a04580491e2: e8 59 fe ff ff call 8049040 <puts@plt>80491e7: 83 c4 10 add $0x10,%esp80491ea: eb 57 jmp 8049243 <main+0xc1>80491ec: 83 ec 0c sub $0xc,%esp80491ef: 68 47 a0 04 08 push $0x804a04780491f4: e8 47 fe ff ff call 8049040 <puts@plt>80491f9: 83 c4 10 add $0x10,%esp80491fc: eb 45 jmp 8049243 <main+0xc1>80491fe: 83 ec 0c sub $0xc,%esp8049201: 68 49 a0 04 08 push $0x804a0498049206: e8 35 fe ff ff call 8049040 <puts@plt>804920b: 83 c4 10 add $0x10,%esp804920e: eb 33 jmp 8049243 <main+0xc1>8049210: 83 ec 0c sub $0xc,%esp8049213: 68 4b a0 04 08 push $0x804a04b8049218: e8 23 fe ff ff call 8049040 <puts@plt>804921d: 83 c4 10 add $0x10,%esp8049220: 83 ec 0c sub $0xc,%esp8049223: 68 4d a0 04 08 push $0x804a04d8049228: e8 13 fe ff ff call 8049040 <puts@plt>804922d: 83 c4 10 add $0x10,%esp8049230: eb 11 jmp 8049243 <main+0xc1>8049232: 83 ec 0c sub $0xc,%esp8049235: 68 4f a0 04 08 push $0x804a04f804923a: e8 01 fe ff ff call 8049040 <puts@plt>804923f: 83 c4 10 add $0x10,%esp8049242: 90 nop8049243: b8 00 00 00 00 mov $0x0,%eax8049248: 8b 4d fc mov -0x4(%ebp),%ecx804924b: c9 leave804924c: 8d 61 fc lea -0x4(%ecx),%esp804924f: c3 ret详解：只看switch部分
80491b7: 8b 45 f4 mov -0xc(%ebp),%eax //把-0xc(%ebp)赋给%eax80491ba: 83 f8 06 cmp $0x6,%eax80491bd: 77 73 ja 8049232 <main+0xb0> //大于就跳转804923280491bf: 8b 04 85 54 a0 04 08 mov 0x804a054(,%eax,4),%eax80491c6: ff e0 jmp *%eax //间接跳转 跳到eax对应的值内80491c8: 83 ec 0c sub $0xc,%esp80491cb: 68 43 a0 04 08 push $0x804a04380491d0: e8 6b fe ff ff call 8049040 <puts@plt>80491d5: 83 c4 10 add $0x10,%esp80491d8: eb 69 jmp 8049243 <main+0xc1> //无条件跳转24380491da: 83 ec 0c sub $0xc,%esp80491dd: 68 45 a0 04 08 push $0x804a04580491e2: e8 59 fe ff ff call 8049040 <puts@plt>80491e7: 83 c4 10 add $0x10,%esp80491ea: eb 57 jmp 8049243 <main+0xc1>//无条件跳转24380491ec: 83 ec 0c sub $0xc,%esp80491ef: 68 47 a0 04 08 push $0x804a04780491f4: e8 47 fe ff ff call 8049040 <puts@plt>80491f9: 83 c4 10 add $0x10,%esp80491fc: eb 45 jmp 8049243 <main+0xc1>//无条件跳转24380491fe: 83 ec 0c sub $0xc,%esp8049201: 68 49 a0 04 08 push $0x804a0498049206: e8 35 fe ff ff call 8049040 <puts@plt>804920b: 83 c4 10 add $0x10,%esp804920e: eb 33 jmp 8049243 <main+0xc1>//无条件跳转2438049210: 83 ec 0c sub $0xc,%esp8049213: 68 4b a0 04 08 push $0x804a04b8049218: e8 23 fe ff ff call 8049040 <puts@plt>804921d: 83 c4 10 add $0x10,%esp8049220: 83 ec 0c sub $0xc,%esp8049223: 68 4d a0 04 08 push $0x804a04d8049228: e8 13 fe ff ff call 8049040 <puts@plt>804922d: 83 c4 10 add $0x10,%esp8049230: eb 11 jmp 8049243 <main+0xc1>//无条件跳转2438049232: 83 ec 0c sub $0xc,%esp8049235: 68 4f a0 04 08 push $0x804a04f804923a: e8 01 fe ff ff call 8049040 <puts@plt>804923f: 83 c4 10 add $0x10,%esp8049242: 90 nop8049243: b8 00 00 00 00 mov $0x0,%eax8049248: 8b 4d fc mov -0x4(%ebp),%ecx804924b: c9 leave804924c: 8d 61 fc lea -0x4(%ecx),%esp804924f: c3 ret
C语言代码参考
#include <stdio.h>
int main()
{int a;scanf("%d", &a);printf("评测结果：成功\n评测脚本：C\n返回结果：");switch (a){ case 1:printf("1\n");break;//**********Begin********case 2:printf("2\n");break;case 3:printf("3\n");break;case 4:printf("4\n");break;case 5:printf("5\n");printf("6\n");break;case 6:printf("6\n");break;default: printf("else"); break;//**********End**********}return 0;
}3 循环结构分析
3.1 for 循环结构
08049172 <main>:8049172: 8d 4c 24 04 lea 0x4(%esp),%ecx8049176: 83 e4 f0 and $0xfffffff0,%esp8049179: ff 71 fc pushl -0x4(%ecx)804917c: 55 push %ebp804917d: 89 e5 mov %esp,%ebp804917f: 51 push %ecx8049180: 83 ec 14 sub $0x14,%esp8049183: c7 45 f4 00 00 00 00 movl $0x0,-0xc(%ebp)804918a: 83 ec 08 sub $0x8,%esp804918d: 8d 45 f0 lea -0x10(%ebp),%eax8049190: 50 push %eax8049191: 68 08 a0 04 08 push $0x804a0088049196: e8 b5 fe ff ff call 8049050 <__isoc99_scanf@plt>804919b: 83 c4 10 add $0x10,%esp804919e: eb 0c jmp 80491ac <main+0x3a>80491a0: 8b 55 f0 mov -0x10(%ebp),%edx80491a3: 8b 45 f0 mov -0x10(%ebp),%eax80491a6: 0f af c2 imul %edx,%eax80491a9: 01 45 f4 add %eax,-0xc(%ebp)80491ac: 8b 45 f0 mov -0x10(%ebp),%eax80491af: 8d 50 ff lea -0x1(%eax),%edx80491b2: 89 55 f0 mov %edx,-0x10(%ebp)80491b5: 85 c0 test %eax,%eax80491b7: 75 e7 jne 80491a0 <main+0x2e>80491b9: 83 ec 08 sub $0x8,%esp80491bc: ff 75 f4 pushl -0xc(%ebp)80491bf: 68 08 a0 04 08 push $0x804a00880491c4: e8 67 fe ff ff call 8049030 <printf@plt>80491c9: 83 c4 10 add $0x10,%esp80491cc: b8 00 00 00 00 mov $0x0,%eax80491d1: 8b 4d fc mov -0x4(%ebp),%ecx80491d4: c9 leave80491d5: 8d 61 fc lea -0x4(%ecx),%esp80491d8: c3 ret详解：只看for循环结构
804919e: c7 45 f4 00 00 00 00 movl $0x0,-0xc(%ebp) //把立即数0赋给地址80491a5: eb 0a jmp 80491b1 <main+0x3f>//跳转80491a7: 8b 45 f4 mov -0xc(%ebp),%eax //i值传递80491aa: 01 45 f0 add %eax,-0x10(%ebp)// i+sum80491ad: 83 45 f4 01 addl $0x1,-0xc(%ebp)//i++80491b1: 8b 45 ec mov -0x14(%ebp),%eax //n值传递80491b4: 39 45 f4 cmp %eax,-0xc(%ebp) //比较i与n80491b7: 7c ee jl 80491a7 <main+0x35> //小于跳转80491b9: 83 ec 08 sub $0x8,%esp80491bc: ff 75 f0 pushl -0x10(%ebp)80491bf: 68 08 a0 04 08 push $0x804a00880491c4: e8 67 fe ff ff call 8049030 <printf@plt>80491c9: 83 c4 10 add $0x10,%esp80491cc: b8 00 00 00 00 mov $0x0,%eax80491d1: 8b 4d fc mov -0x4(%ebp),%ecx80491d4: c9 leave80491d5: 8d 61 fc lea -0x4(%ecx),%esp80491d8: c3 ret
C语言代码参考
#include <stdio.h>int main()
{int n, i, sum = 0;scanf("%d", &n);printf("评测结果：成功\n评测脚本：C\n返回结果：");//此行不在汇编代码中//**********Begin**********for(i=1;i<n;i++){sum+=i;}//**********End**********printf("%d", sum);return 0;
}3.2 while 循环结构
08049172 <main>:8049172: 8d 4c 24 04 lea 0x4(%esp),%ecx8049176: 83 e4 f0 and $0xfffffff0,%esp8049179: ff 71 fc pushl -0x4(%ecx)804917c: 55 push %ebp804917d: 89 e5 mov %esp,%ebp804917f: 51 push %ecx8049180: 83 ec 14 sub $0x14,%esp8049183: c7 45 f4 00 00 00 00 movl $0x0,-0xc(%ebp)804918a: 83 ec 08 sub $0x8,%esp804918d: 8d 45 f0 lea -0x10(%ebp),%eax8049190: 50 push %eax8049191: 68 08 a0 04 08 push $0x804a0088049196: e8 b5 fe ff ff call 8049050 <__isoc99_scanf@plt>804919b: 83 c4 10 add $0x10,%esp804919e: eb 0c jmp 80491ac <main+0x3a>80491a0: 8b 55 f0 mov -0x10(%ebp),%edx80491a3: 8b 45 f0 mov -0x10(%ebp),%eax80491a6: 0f af c2 imul %edx,%eax80491a9: 01 45 f4 add %eax,-0xc(%ebp)80491ac: 8b 45 f0 mov -0x10(%ebp),%eax80491af: 8d 50 ff lea -0x1(%eax),%edx80491b2: 89 55 f0 mov %edx,-0x10(%ebp)80491b5: 85 c0 test %eax,%eax80491b7: 75 e7 jne 80491a0 <main+0x2e>80491b9: 83 ec 08 sub $0x8,%esp80491bc: ff 75 f4 pushl -0xc(%ebp)80491bf: 68 08 a0 04 08 push $0x804a00880491c4: e8 67 fe ff ff call 8049030 <printf@plt>80491c9: 83 c4 10 add $0x10,%esp80491cc: b8 00 00 00 00 mov $0x0,%eax80491d1: 8b 4d fc mov -0x4(%ebp),%ecx80491d4: c9 leave80491d5: 8d 61 fc lea -0x4(%ecx),%esp80491d8: c3 ret详解：只看while循环结构
804919e: eb 0c jmp 80491ac <main+0x3a>//无条件跳转80491a0: 8b 55 f0 mov -0x10(%ebp),%edx80491a3: 8b 45 f0 mov -0x10(%ebp),%eax80491a6: 0f af c2 imul %edx,%eax80491a9: 01 45 f4 add %eax,-0xc(%ebp) //sum=sum+n*n80491ac: 8b 45 f0 mov -0x10(%ebp),%eax80491af: 8d 50 ff lea -0x1(%eax),%edx //减去一80491b2: 89 55 f0 mov %edx,-0x10(%ebp)80491b5: 85 c0 test %eax,%eax80491b7: 75 e7 jne 80491a0 <main+0x2e>//非0跳转80491b9: 83 ec 08 sub $0x8,%esp80491bc: ff 75 f4 pushl -0xc(%ebp)80491bf: 68 08 a0 04 08 push $0x804a00880491c4: e8 67 fe ff ff call 8049030 <printf@plt>80491c9: 83 c4 10 add $0x10,%esp80491cc: b8 00 00 00 00 mov $0x0,%eax80491d1: 8b 4d fc mov -0x4(%ebp),%ecx80491d4: c9 leave80491d5: 8d 61 fc lea -0x4(%ecx),%esp80491d8: c3 ret
C语言代码参考
#include <stdio.h>int main()
{int n, sum = 0;scanf("%d", &n);printf("评测结果：成功\n评测脚本：C\n返回结果：");//此行不在汇编代码中//**********Begin********while(n>0){n--;sum=sum+n*n;}//**********End**********printf("%d", sum);return 0;
}
