ASM: Drawing a Checkerboard

Someone asked a question on a C++ Newgroup about how to draw a checkerboard. Of course, I wasn't satisfied doing this in C++, and I've been looking for a ASM task to do just for practice. This is what I whipped up really quick. The following example will set the video mode to 320x200x256 VGA mode, and draw a black and white checkerboard.

The comments don't belong, I just added them so it is easier to follow. The following was done using DOS Debug.

--Initialize to 320*200*256 color mode
MOV     AX,0013
INT     10
--Point the data and extra segments to the video memory directly and clear the DI register
MOV     AX,A000
MOV     DS,AX
MOV     ES,AX
XOR     DI,DI
--Set AX to the first pallete entry (using 2 byte for the STOSW instructions instead of one)
--Set BX to second one. We will swap these after our checkerboard rows are done
MOV     AX,0F0F
MOV     BX,0000
--initialize CX, our outmost loop, to the number of rows to draw
MOV     CX,0008
PUSH    CX
--set CX, the middle loop, set to the number of times we need to draw a line pattern for the square
--The way it works is like this, there are 8 pattern breaks in a line (black white alternations).
--we need to repeat that alternation 25 times in order to make a single increment of that alteration
--on the veritcal plane, so 25 * 8 = 200
MOV     CX,00C8
PUSH    CX
--set Cx to the number of horizontal pixels in a square, which is 20 (320 / 8) = 160, which
--is the 320 / 2 since we are using a word instruction, not a byte instruction
MOV     CX,0014
--copy what is in AX to video memory 20 times
REPZ
STOSW
--swap the pallete bytes
PUSH    AX
MOV     AX,BX
POP     BX
--get the value of our middle loop
POP     CX
LOOP    011B
--we are at the end of a single verital iteration, swap the pallete entries and go again, until
--the outtermost loop is at 0
PUSH    AX
MOV     AX,BX
POP     BX
POP     CX
LOOP    0117
--wait for keypress
MOV     AH,10
INT     16
--reset video mode
MOV     AX,0003
INT     10
--return to dos
MOV     AX,4C00
INT     21