Question

For my assignment, I'm trying to write Insert function like C++ insert.
My function should insert one string into other string at a certain position.

Inputs:

destination : Be my friend today
source : good
position : 6

Output: Be my good friend today

How should I make room in the middle of the string ?

This is my code so far.

Insert PROC PROC uses edi esi ebx ecx,
destination:DWORD ,
source:DWORD,
position:DWORD
  
mov esi,destination ;add esi address of str
add esi,position
add esi,4 ;lenght of source
mov edi,destination   
   add edi,position
  
;I don't know what should I do in here
  
;How should I make room in the middle of destination ?
;How should I insert at certain position + source length :-(
;Also, I shouldn't use loop and lea.

rep movsb
  
Insert ENDP