This is a good code for LCD beginner. But I still found some problem and hope can be resolve.

;to display "Hello There" from port 1 to LCD
;port 3.2 to RS
;port 3.3 to RW
;port 3.4 to Enable


org 8000h
lcdisp:
mov a, #3ch
acall command
mov a, #0eh
acall command
mov a, #06h
acall command
mov a,#01h
acall command
mov a, #87h
acall command
mov a, #'H'
acall display
mov a, #'e'
acall display
mov a, #'l'
acall display
mov a, #'l'
acall display
mov a, #'o'
acall display
mov a, #0c7h
acall command
mov a, #'T'
acall display
mov a, #'h'
acall display
mov a, #'e'
acall display
mov a, #'r'
acall display
mov a, #'e'
acall display
here:
sjmp here

command: 
acall ready
mov p1,a
clr p3.2
clr p3.3
setb p3.4
clr p3.4
ret

display:
acall ready
mov p1, a
setb p3.2
clr p3.3
setb p3.4
clr p3.4
ret

ready:
clr p3.4
mov p1, #0ffh ;ready port1 for input
clr p3.2
setb p3.3 ;read enable

wait:
clr p3.4
setb p3.4
jb p1.7, wait
clr p3.4
ret
end

1. For RS pin at LCD, what is difference if we write it to data register? What if we write it to command register as code above?

2. "Here: Sjmp Here" in the code meaning that the message "Hello There" can display at LCD forever? It refresh the prompt to LCD?

3. I think the problem is with subroutine display. I should clr RW, setb Enable and setb RS then only "move P1, a" then clr Enable, right?