ddram_address equ 50h
length        equ 51h
mov ddram_address,#80h ;first line of lcd
call shifting
...
...
...



shifting:
mov length,#0
mov dptr,#mess
loop:
mov a,ddram_address
call address
mov a,length
movc a@a+dptr
call write_on
inc length
mov a,length
cjne a,#20,loop
ret

mess: db "<welcome to system!>"

write_on and address is subroutines from 
http://www.8052.com/codelib/lcd_kepad.asm