大会code继续显示故障段 [英] Assembly Code keep showing segment fault

问题描述

为什么本次大会code组装和运行时的链接罚款，但显示段故障。该指令后评论给一个知道我想做的事。

Why this assembly code assemble and link fine but show segment fault in runtime. Commented after the instruction to give a idea what I wanted to do.

  jmp short init

action:
  pop esi
  xor eax, eax
  mov byte [esi+24], al ;null terminating the string.
  mov dword [esi+25],24 ;length of the string

  mov al,4 ;syscall write
  mov ebx,1 ;standard out
  lea ecx,[esi]   ;<<---------- Unsure about this. probably load the address of the string to ecx  
  mov edx,[esi+25] ;<<-- load edx with string length
  int 80h


init:
  call action
  db "what a pity! not working#LLLL"

我使用 NASM 组装和 LD 链接。这个程序将运行在64位计算机上，但我希望它是32位兼容。

I am using NASM to assemble and ld to link. This program will run on a 64-bit machine but I want it to be 32-bit compatible.

推荐答案

您想拥有的字符串在 ECX 的地址。那么，为什么你流行ESI ？使用 POP ECX ，你已经拥有它在正确的寄存器。你不需要它无论如何用于其他目的。

You want to have the address of the string in ecx. So why do you pop esi ? Use pop ecx and you already have it in the correct register. You don't need it anyway for some other purpose.

除此之外，你写入code段，这是不是在默认情况下写的。

Apart from that, you are writing to the code segment, which is not writable by default.

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