# For-loops:

For-loop in C:

``````for(int x = 0; x<=3; x++)
{
//Do something!
}
``````

The same loop in 8086 assembler:

``````        xor cx,cx   ; cx-register is the counter, set to 0
loop1   nop         ; Whatever you wanna do goes here, should not change cx
inc cx      ; Increment
cmp cx,3    ; Compare cx to the limit
jle loop1   ; Loop while less or equal
``````

That is the loop if you need to access your index (cx). If you just wanna to something 0-3=4 times but you do not need the index, this would be easier:

``````        mov cx,4    ; 4 iterations
loop1   nop         ; Whatever you wanna do goes here, should not change cx
loop loop1  ; loop instruction decrements cx and jumps to label if not 0
``````

If you just want to perform a very simple instruction a constant amount of times, you could also use an assembler-directive which will just hardcore that instruction

``````times 4 nop
``````

# Do-while-loops

Do-while-loop in C:

``````int x=1;
do{
//Do something!
}
while(x==1)
``````

The same loop in assembler:

``````        mov ax,1
loop1   nop         ; Whatever you wanna do goes here
cmp ax,1    ; Check wether cx is 1
je loop1    ; And loop if equal
``````

# While-loops

While-loop in C:

``````while(x==1){
//Do something
}
``````

The same loop in assembler:

``````        jmp loop1   ; Jump to condition first
cloop1  nop         ; Execute the content of the loop
loop1   cmp ax,1    ; Check the condition
``````

For the for-loops you should take the cx-register because it is pretty much standard. For the other loop conditions you can take a register of your liking. Of course replace the no-operation instruction with all the instructions you wanna perform in the loop.

``````Do{
AX = 0
AX = AX + 5
BX = 0
BX= BX+AX
} While( AX != BX)
``````

Do while loop always checks the loop the condition at the end of each iteration.