Smoke - random

gistfile1.asm

randomize_lines:
	
	mov	cx, 640			; we're going to set two rows of pixels
					; at the bottom of the screen to be 
					; random colours, so that's 640 pixels
							
	mov	di, 63360		; we're going to start writing these 
					; pixels on the last two lines so that's
					; 64000 - 640
							
next_rand_pixel:

	mov	dx, 40h			; we get quasi-random values from port 40h
	in	al, dx
	
	stosb				; store the pixel on screen
	dec	cx			; move onto the next pixel
	jnz	next_rand_pixel
	
	ret