WRITE_TEXT:  SETB   EN    1 4 7 
             SETB   RS 
             CLR    RW 
             MOV    P0,A 
             CLR    EN 
             LCALL  WAIT_LCD 
             POP    DPH 
             POP    DPL
;;;;;;;;;LJMP DSPL_STR 
             call   DSPL_STR    2 5 8
             ret 


DSPL_STR:    CLR    A 
             MOVC   A,@A+DPTR 
             INC    DPTR 
             PUSH   DPL 
             PUSH   DPH 
;;;;;;;;;;;;;;             CJNE A,#0FFH,WRITE_TEXT
             cjne   a,#0ffh,writeit 
done:        POP    DPH 
             POP    DPL 
             RET

writeit:     call   WRITE_TEXT  3 6 9....
             jmp    done

I "de-smarted your code and from the above you should be able to see what happens. You may think replacing a call/ret with a jmp is smart, all it does is to confuse the $#!+ out of anyone.

Erik