format PE entry start section '.data' data readable writeable cs_string DB "copy me", 0 r_string DB " " section '.text' code readable executable start: push cs_string push r_string call strcpy add esp, 8 int 3 strcpy: push ebp mov ebp, esp mov edx, [ebp+08] mov esi, [ebp+0Ch] mov edi, [ebp+08] copy: mov al, [esi] mov [edi], al inc esi inc edi cmp al, 0 jne copy mov eax, edx pop ebp ret