Tiny question

[Kyrios]

Hi,

There's something OPs which is still bothering me.
1. What's the difference between Pushad and Pushfd?
2. What eip stands for?
3. I wanna copy some string to another location. Original loc is [ebp-8] which is holding string like wedfreertety3453465dgf==
What i want is copy it to another loc like [00500000] be4 the string is erased. And for RVA 00500000h i write 00500010 for instance. So the new loc for string is now at RVA 00500010.
So what's code injection can i have? Can we use repz stosb command?
Any variant of code injection are welcome.


TIA,
kyrios