Question

I want to draw a square in Assembly language. I have ridden something about int 10h. Does anybody know, how to do it? Please place here some piece of code to tell what can I use for drawing a square, or some quality tutorials. Thanks.

Answer 1

Like Frederic Hamidi said, “int 0x10h” is an obsolete BIOS interface. If you’re interested in assembly, I would strongly encourage to AVOID 16-bit, DOS/Masm tutorials and learn on a more modern OS (like Linux).

I’d highly recommend “Programming from the Ground Up”, by Jonathan Bartlett:

http://savannah.nongnu.org/projects/pgubook/

Nevertheless, if you REALLY want to draw a line (or a square) in 16-bit real mode (i.e. in DOS), here’s an example:

http://lateblt.tripod.com/asm.htm

; Draw a line in a graphics mode

;By extension, draws a yellow line in the upper-left.
;A good example of how to efficiently use INC, CMP,
;and a conditional jump for repetitive tasks.

mov ah,00h
mov al,13h
int 10h

;The above three lines just switch to 320x200 256-color VGA.

mov ds,40960
;a000h = 40960 decimal
mov ax, 44h
;44h is yellow! ;)
mov bx,0000
START:
mov [bx],ax
inc bx
cmp bx,20
JL START

;This waits until BX reaches 20, then exits!

mov ah,004C  ;terminate program
int 21h