在汇编语言中检查空字符 [英] Check null character in assembly language

问题描述

我是汇编语言的新手.需要明确的是，这是家庭作业.问题是给出了一个char *list，我怎样才能找到哪个字符是字符串的结尾呢?所以我有

I am new to assembly language. To be clear, this is homework. The problem is given a char *list, how can I find which character is the end of the string? So I have

xor ecx, ecx; //counter
loop1:
mov esi, list;
mov eax, [esi + ecx];
cmp eax, 0x00; //check if the character is null
je end;
inc ecx;
jmp loop1;

end:

然而，循环在到达字符串末尾时不会终止.我想知道我做错了什么.我一直在书籍和网上寻找解决方案，但它们看起来都像我所做的.任何帮助将不胜感激！

however, the loop does not terminate when it reaches the end of the string. I wonder what I have done wrong. I have been finding solution in books and online, but they all look like what I did. Any help will be appreciated!

是的，计数器应该在循环之外.

yes, counter should be outside of the loop.

推荐答案

• 您不应将计数器重置为循环的一部分.
• 您不应将地址初始化为循环的一部分.
• 零终止只是一个字节，但您要测试一个完整的双字.
• 跳转越少，编写的代码越好

把所有这些放在一起，我们得到

Putting all of this together we get

  mov esi, list
  mov ecx, -1
loop1:
  inc ecx
  cmp byte [esi + ecx], 0x00; //check if the character is null
  jne loop1;

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