[Madness]

Примерно так:

count dd 0
text db "WELCOME IMHO",0

begin:
          cld
          mov ecx, end-begin
          mov edi, offset end
          mov esi, offset begin
          rep movsb
          inc [count]
          invoke SendDlgItemMessage, hwnddlg, ID_LISTBOX, LB_ADDSTRING, 0, offset text
          cmp eax, 1000000
          jne end
          ret
end:

dup db 1000000*(end-begin) (?)