汇编学习二-续

  1. 由于对VB分析学习遇到了许多问题，所以就通过c语言的指针来了解VB的变体变量函数。写了一个简单的c :
 1 #include<stdio.h>
 2 #include<string.h>
 3 void test(char *str){
 4     puts(str);
 5 }
 6 int main(){
 7     char str[20]={"hello world!"};
 8     char *p=NULL;
 9     p=str;
10     test(p);
11     getchar();
12     return 0;
13 }

代码比较简单，所以就直接上汇编了。

 1 00401500  /$  55            push ebp
 2 00401501  |.  89E5          mov ebp,esp
 3 00401503  |.  83EC 18       sub esp,0x18
 4 00401506  |.  8B45 08       mov eax,[arg.1]                                               ; |
 5 00401509  |.  890424        mov dword ptr ss:[esp],eax                                    ; |
 6 0040150C  |.  E8 37110000   call <jmp.&msvcrt.puts>                                       ; \puts
 7 00401511  |.  C9            leave
 8 00401512  \.  C3            retn
 9 00401513  /$  55            push ebp                                                      ;  函数开始
10 00401514  |.  89E5          mov ebp,esp
11 00401516  |.  83E4 F0       and esp,0xFFFFFFF0
12 00401519  |.  83EC 30       sub esp,0x30
13 0040151C  |.  E8 AF090000   call point1.00401ED0
14 00401521  |.  C74424 18 686>mov dword ptr ss:[esp+0x18],0x6C6C6568                        ;  hello world! 的首地址（0022fed8）
15 00401529  |.  C74424 1C 6F2>mov dword ptr ss:[esp+0x1C],0x6F77206F
16 00401531  |.  C74424 20 726>mov dword ptr ss:[esp+0x20],0x21646C72                        ;  上面三行用于将hello world！入栈
17 00401539  |.  C74424 24 000>mov dword ptr ss:[esp+0x24],0x0
18 00401541  |.  C74424 28 000>mov dword ptr ss:[esp+0x28],0x0
19 00401549  |.  C74424 2C 000>mov dword ptr ss:[esp+0x2C],0x0
20 00401551  |.  8D4424 18     lea eax,dword ptr ss:[esp+0x18]                               ;  eax=0022fed8='hello world'
21 00401555  |.  894424 2C     mov dword ptr ss:[esp+0x2C],eax                               ;  0022feec='hello world'
22 00401559  |.  8B4424 2C     mov eax,dword ptr ss:[esp+0x2C]
23 0040155D  |.  890424        mov dword ptr ss:[esp],eax                                    ;  0022fec0='hello world'
24 00401560  |.  E8 9BFFFFFF   call point1.00401500                                          ；  call test()
25 00401565  |.  E8 E6100000   call <jmp.&msvcrt.getchar>                                    ; [getchar
26 0040156A  |.  B8 00000000   mov eax,0x0
27 0040156F  |.  C9            leave
28 00401570  \.  C3            retn
29 
30

很明显，函数内的变量是用地址来操作的，只不过不同于VB,c语言中是asicll码，在VB中是以Unicode来存储的。如果看懂了这个，就可以回https://www.cnblogs.com/wlpk/p/12447460.html

posted @ 2020-03-12 16:36  呵哒wlp  阅读(169)  评论(0)  编辑  收藏  举报