While, Do While, For loops in Assembly Language (emu8086)

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-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-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
 je cloop1 ; Jump to content of the loop if
            met

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.