How to set 1 second time delay at assembly language 8086
My problem is that I have written a code that is supposed to output a result into a set of LEDs connected to the parallel port. When I ran the code it pretty much did nothing. My instructor told me that the code ran too fast that my eyes did not see what happened.
I have found that there are a couple of ways to do a time delay, I have tried to loop the NOP but I think I cannot really determine what is going on. Is there any better way?
I have here a part of the code where I have to add a time delay into:
org 100h
mov ax, 0
mov dx, 378
out dx, ax
mov ax, 1
; 1st
mov cx, 1ah
start1st:
mov ax, 1
left:
out dx, ax
; --------------------------------> how to loop?
mov bx, 2
mul bx
cmp ax, 80h
jl left
dec cx
cmp cx,0
jg start1st
; end 1st
Answer
Set 1 million microseconds interval (1 second) By using below instruction .
MOV CX, 0FH
MOV DX, 4240H
MOV AH, 86H
INT 15H
You can set multiple second delay by using 86H and INT 15H
check these links for more details
Waits a specified number of microseconds before returning control to the caller