🚀 go-pugleaf

for drawing on 13h, u will draw in memory first (in an array) and then use
 repz movsw to move it out to screen. that will be the fastest routine to 
do it!

if u do the same for modeY or X, then it will be very slow! it will be ten
times slower if u draw to array first then flip to screen!


to cut down the speed difference, flip to 1st page and draw the screen directly
to second page.


eg.	OUT &H3D4,12 : OUT &H3D5,0      ; flip to 1st page
	CALL DRAWX( &HA400 )		; draw to second page

in this way, u will be drawing while displaying a page!

i have been using modex, modey for quite some time and found that this is the
faster way. but it will still be slower than 13h (by around two times)

anyway, why waste this flicker-free mode and use 13h, which jerks when doing
large scrollings?

anyone try programming 360x480x256 ?     this mode causes even more trouble!