如何在x86汇编代码，at＆t语法中复制单词

Question

So i am working on a project to help me learn assembly and ran into a problem. I need to take a word that was entered by keyboard and copy it so that i can manipulate it after, replace parts of it. I know i have to use a for loop and maybe a stack. I have tried several ways but all my code was wrong and didnt compile. I got the rest of the code to work just not this part, any help would be greatly appreciated in regards to this problem and and good books or websites to help learn assembly would be very welcome. Thank you.

mov $0, $edi

Loop:
  cmp $4, %edi
  jg End

  mov $33, Text(%edi)
  add $1, %edi
  jmp Loop
End:

i tried this code to replace every other letter with a !, i think the process to copy would be the same, i am new to this concept. The copy and the ! replace are the last two parts i am having trouble with the other parts i got. Thank you.

Answer 1

This assembles with GNU as:

mov $0, %edi

Loop:
  cmp $4, %edi
  jg End

  movb $33, Text(%edi)
  add $1, %edi
  jmp Loop
End: