Text display

[maintain3r]

Hi everyone!

I'm pretty new to assembler and I need your help to solve the following problem. I would like to create a DOS program which will display "Hello world" message with typewriter effect.
I'm not asking to provide me with solution, merely to direct me in the right way so I can learn how it can be done.

Thanks in advance and have a nice day!

 

[Salem]

This ->

http://www.ctyme.com/intr/rb-0100.htm

Plus a delay between characters.
Plus a loop to print the whole string.


--
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.

 

[maintain3r]

Thanks Salem!

So far I've managed to print string character by character but I'm having trouble with the delay part! Here's the code:

code segment

assume cs:code,ds:code

org 100h

Typewriter:
mov si, 0 ; setting the index register

print_next:
mov al,MyString[si] ; obtaining the character to print
cmp al,0 ; is it a 0? If yes that means I've reached
je quit_typing ; the end of my string and should stop

mov ah, 0eh ; writing character in
int 10h ; a teletype mode

mov cx,000fh ; This part is giving me the headache!
mov dx,4240h ; It should cause the delay of half a
mov ah,086h ; second (1000000 msecs), right?
int 15h ; NOT WORKING!! PLEASE HELP!!

inc si ; increment index register to get the next character

jmp next_char ; continue with printing next char


quit_typing:
mov ah, 0 ; wait for user to press some key
int 16h ; and when that happens
ret ; exit and return control to DOS

MyString db 'Hello world!', 0

code ends

end Typewriter

The following link shows exactly what I'm trying to achieve:

http://www.youtube.com/watch?v=oMURyUP1s1Y

You see how that text is being printed? Thanks in advance!

 

[maintain3r]

Hi everyone!

I've managed to finish this little program I would like you to tell me if there is a way (and need) to optimize the code so that it works faster. Here's the code:


code segment
assume cs:code,ds:code
org 100h

Typewriter_pocetak:
xor si,si
mov dh,10
mov dl,25
mov ah,02h
int 10h
sljedeci_znak:
mov al,J3l3n4[si]
cmp al,0
je kraj_ispisa
mov di,5
cmp al,32
je Ispisi
Nastavi_ispis:
mov ah,0eh
int 10h
xor ah,ah
int 1ah
mov bx,dx
Pauza:
xor ah,ah
int 1ah
sub dx,bx
cmp di,dx
ja Pauza
inc si
jmp sljedeci_znak
kraj_ispisa:
int 20h

J3l3n4 db 'Dear user!',10,13,10
db ' Whish you a good day ',10,10,13,0

Ispisi:
mov di,1
jmp Nastavi_ispis

code ends
end Typewriter_pocetak

As you can see I'm willing to learn and that's the reason why I'm asking you to help me. I hope that with your help I'll be able to write better and efficient Assembly code. Thanks in advance!