汇编如何将REP STOS转换为C代码(Assembly How to convert REP STOS to C code)

 我一直在调试REP STOS DWORD PTR ES:[EDI]一段时间 
 
 从我的结论，它总是使用 
 
 ECX作为柜台。 EAX作为将通过EDI复制的值，然后在EDI指向的转储后添加ECX时间 
 
 它似乎覆盖EDI上的指向数据，看起来它总是只使用ECX作为计数器，同时将EDI改为4个字节。 它在计数器达到0时停止工作 
 
 所以我想出了这种代码 
 
while(regs.d.ecx != 0)
{
    *(unsigned int *)(regs.d.edi) = regs.d.eax;
    regs.d.edi += 4;
    regs.d.ecx--;
}
 
 似乎工作..但我很担心，因为我只是通过运气和猜测工作。 它坚实吗？ 就像它始终将ECX作为计数器， EAX作为数据一样，并且始终复制4个字节永远不会更少？ 

I been debugging REP STOS DWORD PTR ES:[EDI] for a while now
 
From my conclusion it always uses 
 
ECX as counter. EAX as the value that will be copied over EDI and then appended ECX times so after putting in the pointed dump of EDI
 
it seems to overwrite the pointed data at EDI with what's it seems it always only uses ECX as a counter, while changing EDI by 4 bytes. it stops working when counter hits 0
 
So I came up with this kind of code
 
while(regs.d.ecx != 0)
{
    *(unsigned int *)(regs.d.edi) = regs.d.eax;
    regs.d.edi += 4;
    regs.d.ecx--;
}
 
Seems to work.. but i'm concerned since I just did this by luck and guess work. Is it solid? like will it always be ECX as counter, EAX as data, and it always copies 4 bytes never less?

原文：https://stackoverflow.com/questions/7763581